36 calculatorsPercentages, statistics, geometry

Math & Statistics

Math calculators handle everything from everyday arithmetic to coursework: percentages and percent change, fractions and decimals, ratios and proportions, averages, median, mode, standard deviation, z-scores, and confidence intervals. There are also tools for geometry, quadratic equations, exponents, logarithms, prime factors, LCM and GCF, rounding, and significant figures. Each one shows the formula and the steps, so you can check the answer and learn the method.

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.
Ratio Calculator Ratio 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 Calculator Percentage 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 Calculator Fraction 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 Calculator Standard deviation calculator for sample (n − 1) or population (n) data: get the variance, mean, standard error and coefficient of variation in one step.
Median Calculator Median calculator: enter numbers to get the median, first and third quartiles, interquartile range, min, max and the sorted data, plus outlier fences.
Weighted Average Calculator Weighted 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 Calculator Probability 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 Calculator Variance 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 Calculator Scientific notation calculator: convert a number to a × 10ⁿ form, E notation and engineering notation, round to significant figures or expand to decimal.
Percentage Increase Calculator Percentage 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 Calculator Mode 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 Calculator Decimal 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 Calculator Fraction to decimal calculator: turn a fraction or mixed number into an exact decimal with the repeating part marked, plus rounded value and percent.
Permutation Calculator Permutation 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 Calculator Combination 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 Calculator Quadratic 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 Calculator Confidence 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 Calculator Z 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 Calculator Sample 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 Calculator Percent error calculator: compare a measurement with the accepted value, get absolute, relative and signed error, or the percent difference of two trials.
Slope Calculator Slope 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 Calculator Pythagorean theorem calculator: find the hypotenuse or a missing leg of a right triangle, with the steps shown, angles, area and Pythagorean triple check.
Circle Calculator Circle 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 Calculator Volume 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 Calculator Triangle 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 Calculator Sig fig calculator: count significant figures exactly as typed, round to N sig figs, and add, subtract, multiply or divide with the right precision.
Rounding Calculator Rounding 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 Calculator LCM 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 Calculator GCF calculator: find the greatest common factor (GCD, HCF) of 2 to 10 whole numbers, with every Euclidean algorithm step and the prime factorizations.
Exponent Calculator Exponent 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 Calculator Prime 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 Calculator Square 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 Calculator Log 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 Generator Random 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.