164 free calculators
Free online calculators that show their work
From mortgages and BMI to paint, GPA, and sales tax, each result comes with its formula, examples, and sources.
FinanceLoans, mortgages, savings, investing
HealthBMI, calories, fitness, sleep
Home & ConstructionMaterials, area, and energy
School & GradesGPA, grades, and finals
- Freeno sign-up
- Formula shownwith worked examples
- Official sourcesrules reviewed
- 5 languageswritten for each market
Browse by category
See all- Health BMI, calories, fitness, sleep
- Finance Loans, mortgages, savings, investing
- Math & Statistics Percentages, statistics, geometry
- Home & Construction Materials, area, and energy
- Everyday Life Tips, recipes, and pets
- Business & Pricing Pricing, margins, and sales
- Auto, Travel & Sport Cars, fuel, speed, and pace
- Taxes Paychecks, brackets, and retirement
- Work & Money Salary, overtime, and raises
- Pregnancy & Fertility Due date, ovulation, cycles
- Date & Time Dates, ages, and hours
- Unit Converters Metric, US, and more
- School & Grades GPA, grades, and finals
- All calculators 164 calculators
Popular calculators
Good places to start.
- BMI Calculator Free BMI calculator for adults: enter weight and height in lb/ft-in or kg/cm to get your body mass index, CDC/WHO category and healthy weight range.
- Compound Interest Calculator Free compound interest calculator: see how savings grow with monthly contributions, any compounding frequency and inflation, plus a year-by-year table.
- Proportion Calculator Proportion calculator: enter three values to find the missing fourth with the rule of three. Handles direct and inverse proportions, with worked examples.
- Average Calculator Free average calculator: paste a list of numbers to get the mean, median, sum, count, minimum and maximum, and see when the median tells the truer story.
- Water Intake Calculator Water intake calculator: estimate daily fluids from your weight, exercise, heat, pregnancy or breastfeeding, in fl oz and 8-oz cups, vs. official guidance.
- Tip Calculator Free tip calculator: enter the bill and tip percentage to see the tip, the total and each person's share, with optional rounding up of the total or shares.
- Sales Tax Calculator Free sales tax calculator with 2026 state and average local rates for all 50 states and DC. Add tax to a price or back it out of a tax-inclusive total.
- Discount Calculator Free discount calculator: find the sale price and how much you save, stack an extra percent off correctly, and add sales tax on the discounted price.
All calculators
Health
16 calculators- BMI CalculatorFree BMI calculator for adults: enter weight and height in lb/ft-in or kg/cm to get your body mass index, CDC/WHO category and healthy weight range.
- Water Intake CalculatorWater intake calculator: estimate daily fluids from your weight, exercise, heat, pregnancy or breastfeeding, in fl oz and 8-oz cups, vs. official guidance.
- Macro CalculatorMacro calculator: estimate your daily calories and grams of protein, carbs and fat from the Mifflin-St Jeor equation, your activity level and your goal.
- Protein CalculatorProtein calculator: see how many grams of protein you need a day based on your weight, age and activity, with a range, a per-meal target and calories.
- Body Fat CalculatorBody fat calculator: estimate your body fat percentage with the US Navy tape-measure method or from BMI, and see your fat mass, lean mass and ACE category.
- TDEE CalculatorTDEE calculator: estimate how many calories you burn a day from your BMR and activity level, with targets to lose or gain weight and all 5 activity levels.
- Calorie CalculatorCalorie calculator: how many calories a day to eat to lose, maintain or gain weight at 0.5 to 2 lb a week, with a built-in minimum and all goals compared.
- BMR CalculatorBMR calculator: estimate the calories your body burns at rest with Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle, per day, per hour and in kJ.
- Heart Rate Zone CalculatorHeart rate zone calculator: find your max heart rate (Tanaka, 220 − age or measured) and five training zones in bpm, with Karvonen if you add resting HR.
- Ideal Weight CalculatorIdeal weight calculator: see the healthy weight range for your height (BMI 18.5–24.9) and the Devine, Robinson, Miller and Hamwi formulas, in lb or kg.
- Calorie Deficit CalculatorCalorie deficit calculator: estimate your TDEE, a daily calorie target for weight loss, pounds lost per week and how many weeks it may take to hit a goal.
- Waist to Hip Ratio CalculatorWaist to hip ratio calculator: divide waist by hips, compare your WHR with WHO cut-offs, check your waist against NIH guidance and see waist-to-height.
- Lean Body Mass CalculatorLean body mass calculator: estimate your LBM from height, weight and sex with the Boer, James and Hume formulas, or from your body fat percentage if known.
- One Rep Max CalculatorOne rep max calculator: estimate your 1RM from one set of 1–12 reps with six classic formulas (Epley, Brzycki and more) plus a load chart for 1–12 reps.
- BAC CalculatorBAC calculator: a rough Widmark estimate of blood alcohol from drinks, weight and time. It can’t say if it’s safe or legal to drive. Don’t drink and drive.
- Sleep CalculatorSleep calculator: find when to go to bed for your wake-up time, or when to wake up, using 90-minute sleep cycles and CDC recommended hours for your age.
Finance
33 calculators- Compound Interest CalculatorFree compound interest calculator: see how savings grow with monthly contributions, any compounding frequency and inflation, plus a year-by-year table.
- Future Value CalculatorFuture value calculator: find what a lump sum plus regular deposits will be worth, with annual, quarterly or monthly compounding and payment timing.
- ROI CalculatorROI calculator: work out return on investment from what you put in, what you got back and extra costs, plus the annualized ROI over any holding period.
- Credit Card Payoff CalculatorCredit card payoff calculator: see how many months it takes to clear your balance, the total interest you'll pay, or the payment to be debt-free by a date.
- Investment CalculatorInvestment calculator: project how a lump sum and monthly contributions could grow, with yearly increases, fund fees, inflation and a year-by-year table.
- Savings CalculatorSavings calculator: see how a starting balance and monthly deposits grow at your APY, or find how much to save each month to reach a savings goal on time.
- Loan CalculatorFree loan calculator: enter the amount, interest rate and term to see your monthly payment, total interest and a year-by-year amortization schedule.
- Retirement CalculatorRetirement calculator: project your savings to retirement in today's dollars, compare them with the nest egg your income goal needs and see the gap.
- Personal Loan CalculatorPersonal loan calculator: get your monthly payment, total interest and true APR, with an origination fee deducted from the loan or added to the balance.
- Budget CalculatorBudget calculator: enter your take-home pay and monthly expenses to see needs, wants and savings as a share of income, compared with the 50/30/20 rule.
- Amortization CalculatorAmortization calculator: see your monthly payment, a yearly amortization schedule and how extra payments or a lump sum cut your interest and payoff date.
- APR CalculatorAPR calculator: add origination fees, points and other finance charges to a loan's interest rate to find the APR, finance charge and monthly payment.
- Mortgage CalculatorMortgage calculator: monthly principal and interest plus property tax, homeowners insurance, HOA and PMI (PITI), with a yearly amortization schedule.
- Simple Interest CalculatorSimple interest calculator using I = Prt: enter principal, rate and time or two dates, pick a day count, and compare the result with compound interest.
- Rent vs Buy CalculatorRent vs buy calculator: compare your net worth after N years when buying with a mortgage or renting and investing the difference, plus the break-even year.
- CAGR CalculatorCAGR calculator: find the compound annual growth rate between two values, by years or exact dates, with dividends, real return and doubling time.
- APY CalculatorAPY calculator: turn an interest rate into annual percentage yield for daily, monthly or quarterly compounding, convert APY back to APR and see interest.
- Emergency Fund CalculatorEmergency fund calculator: set a savings target from your essential monthly expenses, then see how many months it takes to get there, with optional APY.
- Present Value CalculatorPresent value calculator: find what a future amount or a series of equal payments is worth today at your discount rate, with payments at end or start.
- Mortgage Payoff CalculatorMortgage payoff calculator: see how extra monthly payments or a lump sum cut your payoff date and total interest, with the balance year by year.
- Debt Payoff CalculatorDebt payoff calculator: list up to 5 debts, add an extra monthly payment and see your payoff date, total interest and savings with avalanche or snowball.
- Net Worth CalculatorNet worth calculator: add up cash, investments, retirement accounts, home and car, subtract your debts, and see net worth, debt ratio and liquid assets.
- Debt-to-Income Ratio CalculatorDebt to income ratio calculator: enter gross monthly income and debt payments to see your back-end and front-end DTI and how much room is left under 36%.
- Inflation CalculatorInflation calculator: see what a dollar amount from one year is worth in another using official CPI-U data, or project future prices at an inflation rate.
- Interest Rate CalculatorInterest rate calculator: find the rate behind a loan payment, or the growth rate between two values, as a monthly, nominal annual and effective rate.
- Dividend CalculatorDividend calculator: find a stock's dividend yield, your annual, monthly and per-payment income after tax, and a year-by-year projection with DRIP.
- Down Payment CalculatorDown payment calculator: see your down payment, loan amount, LTV, closing costs and total cash needed, whether PMI applies, and how many months to save.
- Effective Annual Rate CalculatorEffective annual rate calculator: convert a nominal rate or APR into the effective annual rate (EAR) for daily, monthly or quarterly compounding, or back.
- Refinance CalculatorRefinance calculator: compare your mortgage with a new loan, including points and closing costs: monthly savings, break-even month and lifetime interest.
- CD CalculatorCD calculator: see the interest a certificate of deposit earns by maturity from its APY or APR, what an early withdrawal penalty costs and tax on interest.
- Rule of 72 CalculatorRule of 72 calculator: estimate the years needed to double, triple or quadruple money at a given rate, or the rate needed, and compare with the exact math.
- Annuity CalculatorAnnuity calculator: find the payment a lump sum can provide, what regular contributions grow to, or the present value of payments, with yearly increases.
- Stock Average CalculatorStock average calculator: find your average cost per share across several buys, including fees, and see how many shares it takes to average down or up.
Math & Statistics
36 calculators- Proportion CalculatorProportion calculator: enter three values to find the missing fourth with the rule of three. Handles direct and inverse proportions, with worked examples.
- Average CalculatorFree average calculator: paste a list of numbers to get the mean, median, sum, count, minimum and maximum, and see when the median tells the truer story.
- Ratio CalculatorRatio calculator: simplify any ratio A:B, see its decimal value and each part's share, or scale it to find a missing side, like 16:9 at 1280 pixels wide.
- Percentage CalculatorPercentage calculator with three modes: find X% of a number, what percent one number is of another, or the whole when you know a part and its percentage.
- Fraction CalculatorFraction calculator: add, subtract, multiply or divide two fractions and get the answer in lowest terms, as a mixed number and as a decimal. Negatives OK.
- Standard Deviation CalculatorStandard deviation calculator for sample (n − 1) or population (n) data: get the variance, mean, standard error and coefficient of variation in one step.
- Median CalculatorMedian calculator: enter numbers to get the median, first and third quartiles, interquartile range, min, max and the sorted data, plus outlier fences.
- Weighted Average CalculatorWeighted average calculator: enter values and their weights to get the weighted mean, the sum of weights and products, and compare it with the simple mean.
- Probability CalculatorProbability calculator for two independent events (A and B, A or B, exactly one, neither) and repeated trials: exactly k, at most k, at least k successes.
- Variance CalculatorVariance calculator for a sample (n − 1) or a population (n): paste your numbers to get variance, standard deviation, mean and a step-by-step table.
- Scientific Notation CalculatorScientific notation calculator: convert a number to a × 10ⁿ form, E notation and engineering notation, round to significant figures or expand to decimal.
- Percentage Increase CalculatorPercentage increase calculator: find the % change from an old to a new value, raise or cut a number by a percent, or get the percent difference of two.
- Mode CalculatorMode calculator: find the most frequent value in a data set, spot bimodal or multimodal data, and get a frequency table plus the mean and median.
- Decimal to Fraction CalculatorDecimal to fraction calculator: exact fraction in lowest terms, mixed number, repeating decimals like 0.1(6) and a close fraction with a set denominator.
- Fraction to Decimal CalculatorFraction to decimal calculator: turn a fraction or mixed number into an exact decimal with the repeating part marked, plus rounded value and percent.
- Permutation CalculatorPermutation calculator: find nPr = n!/(n − r)! or n^r with repetition, exact to the last digit, plus combinations nCr and n! for the same n and r.
- Combination CalculatorCombination calculator: get nCr exactly for n and r up to 1,000, with or without repetition, plus the odds of one combination and permutations.
- Quadratic Equation CalculatorQuadratic equation calculator: solve ax² + bx + c = 0 for real or complex roots, with the discriminant, vertex, factored form and sum and product of roots.
- Confidence Interval CalculatorConfidence interval calculator for a mean (t or z) or a proportion (Wilson and Wald), at 80% to 99.9% confidence, with margin of error and standard error.
- Z-Score CalculatorZ score calculator: turn a raw score into a z-score and percentile, a z-score into one- and two-tailed p-values, or a percentile back into a score.
- Sample Size CalculatorSample size calculator: how many responses a survey needs for a chosen margin of error and confidence level, for a proportion or a mean, in any population.
- Percent Error CalculatorPercent error calculator: compare a measurement with the accepted value, get absolute, relative and signed error, or the percent difference of two trials.
- Slope CalculatorSlope calculator: enter two points to get the slope as a decimal and fraction, the line's equation in three forms, the angle, percent grade and distance.
- Pythagorean Theorem CalculatorPythagorean theorem calculator: find the hypotenuse or a missing leg of a right triangle, with the steps shown, angles, area and Pythagorean triple check.
- Circle CalculatorCircle calculator: enter the radius, diameter, circumference or area to get the other three, exact multiples of π, plus arc length, sector area and chord.
- Volume CalculatorVolume calculator for cubes, boxes, cylinders, cones, spheres and more: get the volume, surface area and the capacity in US gallons, liters and cubic feet.
- Triangle CalculatorTriangle calculator: solve any triangle from three sides, two sides and an angle, or two angles and a side. Get all sides, angles, area, heights and radii.
- Sig Fig CalculatorSig fig calculator: count significant figures exactly as typed, round to N sig figs, and add, subtract, multiply or divide with the right precision.
- Rounding CalculatorRounding calculator: round to a place value, decimal places or the nearest multiple (0.05, 5, 100) and compare half up, banker's, ceiling and floor.
- LCM CalculatorLCM calculator: find the least common multiple of 2 to 10 whole numbers, with the step-by-step lcm = a × b ÷ gcd method and the prime factorizations.
- GCF CalculatorGCF calculator: find the greatest common factor (GCD, HCF) of 2 to 10 whole numbers, with every Euclidean algorithm step and the prime factorizations.
- Exponent CalculatorExponent calculator: find a^b exactly, including big powers like 2^100, negative and fractional exponents, or solve for the exponent or the base.
- Prime Factorization CalculatorPrime factorization calculator: break any whole number up to 10^15 into primes, with factor tree steps, exponent form, divisor count and all divisors.
- Square Root CalculatorSquare root calculator: find √x, cube roots and any nth root, simplify radicals like √72 = 6√2, spot perfect squares and see roots of negative numbers.
- Log CalculatorLog calculator: find log base 10, natural log (ln), log base 2 or any custom base, see the change-of-base steps, or switch to antilog to undo a logarithm.
- Random Number GeneratorRandom number generator: pick 1 to 500 whole or decimal numbers in any range, with no repeats, sorted output, or a seed that repeats the same list.
Home & Construction
20 calculators- Roofing CalculatorFree roofing calculator: enter the footprint in feet, the pitch (x/12) and overhang to get roof area in sq ft, roofing squares and shingle bundles to buy.
- Concrete CalculatorConcrete calculator for slabs, footings and posts: get cubic yards and how many 40, 60 or 80-lb bags to buy, or the cement, sand and gravel to mix by hand.
- Electricity Cost CalculatorElectricity cost calculator: see what any appliance costs per day, month and year from its watts and hours of use, or price your monthly kWh at your rate.
- Paint CalculatorPaint calculator: enter room size, doors, windows and coats to see how many gallons of wall paint to buy, with ceiling option and your can's coverage rate.
- Tile CalculatorTile calculator: enter the floor or wall size, tile size, grout joint and waste to see how many tiles and boxes you need, plus the square footage to order.
- Wallpaper CalculatorWallpaper calculator: enter room size, doors, windows, roll size and pattern repeat to see how many strips and double rolls of wallpaper you need to order.
- Flooring CalculatorFlooring calculator: enter room size, waste and box coverage to see how many boxes of laminate, vinyl plank or engineered wood to buy and the cost.
- Square Footage CalculatorSquare footage calculator for rectangles, L-shaped rooms, circles, triangles and trapezoids: get sq ft, sq yd and m², the perimeter and the cost per sq ft.
- Air Conditioner BTU CalculatorAir conditioner BTU calculator: enter square footage, sun exposure and occupants to see the BTU/h a window or portable AC needs, per the ENERGY STAR chart.
- Mortar CalculatorMortar calculator: enter area, thickness and cement-to-sand ratio to see how many 94-lb bags of cement and how much sand you need for stucco or masonry.
- Brick CalculatorBrick calculator: find how many bricks you need for a wall from its size, door and window openings, brick dimensions and mortar joint, with waste and cost.
- Solar Panel CalculatorSolar panel calculator: estimate the system size in kW, number of panels, roof area, yearly production, savings and simple payback from your electric bill.
- Gravel CalculatorGravel calculator: enter length, width or diameter and depth to estimate cubic yards, tons and bags of gravel, crushed stone, sand or topsoil.
- Fence CalculatorFence calculator: enter up to four sides, post spacing, height and gates to estimate posts, rails, boards or panels and concrete bags for the posts.
- Drywall CalculatorDrywall calculator: enter room size, doors and windows to estimate 4×8, 4×10 or 4×12 sheets, joint compound, tape and screws, with waste and ceiling.
- Mulch CalculatorMulch calculator: enter bed size and depth to see how many cubic yards of bulk mulch or 2 or 3 cu ft bags to buy, with a recommended-depth check.
- Stair CalculatorStair calculator: enter total rise and tread depth to get risers, riser height to 1/16 in, total run, stringer length and the IRC limits checked.
- Pool Volume CalculatorPool volume calculator: enter shape and depth for rectangle, round, oval or kidney pools to get gallons, liters and how long a hose takes to fill it.
- Ohm's Law CalculatorOhm's law calculator: enter any two of voltage, current, resistance and power to get the other two, with mV to kV, mA, kΩ and MΩ units and all 12 formulas.
- How Much Rent Can I Afford?How much rent can I afford? Compare the 30% rule, the 40× rent landlord test and 50/30/20 with your income, utilities and debts; check a candidate rent.
Everyday Life
3 calculators- Tip CalculatorFree tip calculator: enter the bill and tip percentage to see the tip, the total and each person's share, with optional rounding up of the total or shares.
- Recipe Serving CalculatorRecipe serving calculator: scale a recipe to any number of servings and get ingredient amounts rounded to measuring-cup fractions, with tsp, tbsp and cups.
- Dog Age CalculatorDog age calculator: convert your dog's age to human years by size, compare the UC San Diego DNA formula with the ×7 rule and see your dog's life stage.
Business & Pricing
8 calculators- Discount CalculatorFree discount calculator: find the sale price and how much you save, stack an extra percent off correctly, and add sales tax on the discounted price.
- Markup CalculatorFree markup calculator: set a selling price from cost and markup percent, or enter a price to find markup and gross margin. Learn markup vs. margin.
- Unit Price CalculatorUnit price calculator: compare two or three package sizes by price per pound, per fluid ounce or per item and see which is the better deal and by how much.
- Break-Even CalculatorBreak even calculator: find how many units you must sell to cover fixed costs, the sales revenue needed, your contribution margin and margin of safety.
- Business Loan CalculatorBusiness loan calculator: find the payment on a term loan or factor-rate advance, with monthly, weekly or daily payments, fees and the true APR you'd pay.
- Profit Margin CalculatorProfit margin calculator: find gross margin from revenue and cost, net margin after operating expenses, or the price you need to hit a target margin.
- Commission CalculatorCommission calculator: work out sales commission at a flat or tiered rate, split it with a brokerage or co-agent, and add base pay, a draw and withholding.
- CPM CalculatorCPM calculator: find cost per thousand impressions, total ad cost or impressions from the other two, plus CTR, CPC, CPA, ROAS and eCPM for your campaign.
Auto, Travel & Sport
9 calculators- Pace CalculatorRunning pace calculator: find your pace per mile or km, your finish time for a 5K, 10K, half or full marathon, or how far you'll run at a given pace.
- Speed CalculatorSpeed calculator: find average speed from distance and time, distance from speed and time, or travel time, with results in mph, km/h and m/s at once.
- Car Loan CalculatorCar loan calculator: estimate your monthly auto payment with sales tax, trade-in, down payment, dealer fees and an optional balloon, plus total interest.
- Fuel Cost CalculatorFuel cost calculator: enter miles, your car's mpg and the gas price to see trip cost, gallons needed, cost per mile and each person's share of a road trip.
- Fuel Consumption Calculator (MPG)Fuel consumption calculator: enter miles driven and gallons filled to get your real mpg, plus L/100 km, km/L, UK mpg and fuel cost per mile and 100 miles.
- Car Lease CalculatorLease calculator: estimate your monthly car lease payment from price, down payment, residual value and money factor or APR, with sales tax on the payment.
- Mileage CalculatorMileage calculator with the 2026 IRS rates: 76¢ from July 1 or 72.5¢ before, for business, medical, moving or charity miles, plus tolls and parking.
- Cost per Mile CalculatorCost per mile calculator for gas and electric cars: add depreciation, fuel or charging, insurance, registration and upkeep to get your cost per mile.
- Paris Taxi Fare CalculatorParis taxi fare calculator for 2026: CDG and Orly flat rates for the Right or Left Bank, metered Tariffs A, B and C, extras allowed and your rights.
Taxes
6 calculators- Sales Tax CalculatorFree sales tax calculator with 2026 state and average local rates for all 50 states and DC. Add tax to a price or back it out of a tax-inclusive total.
- Self-Employment Tax CalculatorSelf employment tax calculator for 2026: Social Security and Medicare on net profit, the deductible half, quarterly estimates and Additional Medicare.
- 401(k) Calculator401k calculator: project your balance at retirement from salary, contribution rate and employer match, using 2026 IRS limits and catch-up contributions.
- Roth IRA CalculatorRoth IRA calculator: check how much you can contribute in 2026 under the IRS income phase-out, then project your tax-free balance at retirement.
- Tax Bracket Calculator 2026Tax bracket calculator for 2026: see your federal income tax, marginal and effective rate, and how much of your income falls in each IRS bracket.
- Paycheck CalculatorPaycheck calculator for 2026: estimate take-home pay per check after federal withholding, Social Security, Medicare, state tax and pre-tax deductions.
Work & Money
3 calculators- Overtime CalculatorOvertime calculator for hourly or salaried nonexempt workers: time-and-a-half under the FLSA, double time hours, overtime rate and total overtime pay.
- Salary to Hourly CalculatorSalary to hourly calculator: convert an annual, monthly or weekly salary into an hourly wage, or an hourly rate into yearly pay, with unpaid weeks off.
- Pay Raise CalculatorPay raise calculator: see your new salary or hourly rate after a raise in percent or dollars, per paycheck and per year, and whether it beats inflation.
Pregnancy & Fertility
5 calculators- Ovulation CalculatorFree ovulation calculator: enter the first day of your last period and cycle length to estimate ovulation, your fertile window and the next six cycles.
- Pregnancy Week CalculatorPregnancy week calculator: find how many weeks and days pregnant you are, your trimester and due date from your last period, conception or IVF transfer.
- Pregnancy Due Date CalculatorPregnancy due date calculator: estimate your due date from your last period, conception, IVF transfer or an ultrasound, plus weeks pregnant and trimesters.
- Conception CalculatorConception calculator: work back from a due date, a last period or a birth date to the likely date of conception and the fertile window around it.
- Period CalculatorPeriod calculator: predict when your next period starts and ends, see your cycle day, days late and next six periods, with a range for irregular cycles.
Date & Time
12 calculators- Age CalculatorFree age calculator: enter a date of birth to see your exact age in years, months and days, total days and weeks, and the countdown to your next birthday.
- Date CalculatorFree date calculator: add or subtract years, months, weeks and days from any date to get the resulting date, its weekday and the number of days in between.
- Time Duration CalculatorTime duration calculator: find the hours and minutes between two times or two dates, subtract an unpaid break and get decimal hours for your timesheet.
- Time CalculatorTime calculator: add or subtract hours, minutes and seconds, total a timesheet in hours and decimal hours, find the end time and estimate gross pay.
- Business Days CalculatorBusiness days calculator: count the workdays between two dates or add business days to a date, skipping weekends and U.S. federal holidays (observed).
- Date Difference CalculatorDate difference calculator: count the days between two dates, with years, months and days, weeks, weekdays Monday to Friday, total months and hours.
- Days Until CalculatorDays until calculator: count the days to Christmas, Thanksgiving, July 4 or any date you pick, with weeks, months, weekdays and hours, or days since.
- Week Number CalculatorWeek number calculator: find the ISO 8601 week and the US (Sunday-start) week number for any date, or get the Monday–Sunday dates of any ISO week.
- Military Time ConverterMilitary time converter: turn 2:30 PM into 1430 or 1430 back into 2:30 PM, see how the time is said aloud, and use a full 24-hour military time chart.
- Time Card CalculatorTime card calculator: add up a week of start and end times minus unpaid breaks, including overnight shifts, and see regular hours, overtime and gross pay.
- Unix Timestamp ConverterUnix timestamp converter: turn epoch seconds or milliseconds into a UTC and local date with DST, or a date and time into a timestamp. Year 2038 check.
- Time Zone ConverterTime zone converter and world clock: compare up to 10 cities, see US and European daylight saving changes, and find a meeting time that fits every office.
Unit Converters
10 calculators- Power ConverterPower converter for watts, kW, MW, horsepower, metric PS, BTU/h, kcal/h, ft·lbf/s, cal/s and refrigeration tons, with a table of every unit at once.
- Weight ConverterWeight converter for pounds, kilograms, ounces, grams, stone, short and long tons, carats, troy ounces and grains, with every unit shown in one table.
- Unit ConverterUnit converter for length, mass, volume, area, speed, time, pressure, energy, data storage and temperature: US and metric units with exact factors.
- Volume ConverterVolume converter for cups, tablespoons, teaspoons, fluid ounces, pints, quarts, US and imperial gallons, liters, mL, cubic feet and oil barrels.
- Temperature ConverterTemperature converter for Fahrenheit, Celsius, kelvin and Rankine, with the formula used, an oven temperature chart and safe cooking temperatures in °C.
- Area ConverterArea converter for square feet, square meters, acres, hectares, square yards, square inches and square miles, with every unit shown in one table at once.
- Length ConverterLength converter for inches, feet, yards, miles, centimeters, meters and kilometers, plus mils, furlongs and nautical miles, with all units in one table.
- Speed ConverterSpeed converter for mph, km/h, knots, m/s, ft/s, Mach and the speed of light, using exact NIST factors, with every unit at once and running pace per mile.
- Roman Numeral ConverterRoman numeral converter: turn numbers and years into Roman numerals and back, with a place-value breakdown, strict checking and bar notation to 3,999,999.
- Binary ConverterBinary converter for decimal, hex, octal and any base from 2 to 36, with 8- to 64-bit two's complement and text to binary in UTF-8 plus binary to text.
School & Grades
3 calculators- GPA CalculatorFree GPA calculator on the 4.0 scale: enter letter grades and credits to get your semester GPA, a weighted Honors/AP GPA and your cumulative GPA.
- Grade CalculatorGrade calculator for weighted classes: enter category scores or points and syllabus weights to see your current grade, letter grade and what's left.
- Final Grade CalculatorFinal grade calculator: enter your current grade and the final exam's weight to see the score you need for an A, B, C or D, or test a what-if score.
About CalcFolio
CalcFolio offers more than 160 free online calculators covering personal finance, health and fitness, math and statistics, home and construction projects, taxes and paychecks, dates and time, school grades, pregnancy, driving, and unit conversions. There is nothing to sign up for and nothing to install. Every calculator shows its formula and methodology, walks through worked examples, answers common questions, and lists its sources, so you can see how each number was produced. Where a result depends on tax rules or official rates, those rules carry an effective date and are reviewed against official sources. Your inputs are processed in your browser and are not sent to our server.