16 calculatorsBMI, calories, fitness, sleep
Health
Health and fitness calculators turn a few measurements into numbers you can act on or discuss with your doctor: BMI, body fat, ideal weight, daily calories and TDEE, macros and protein, water intake, heart rate zones, one-rep max, blood alcohol, and sleep cycles. Each one explains its formula, the reference ranges it uses, and their sources. They are screening and planning tools, not a diagnosis.
- 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.
- 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.
- Macro Calculator Macro 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 Calculator Protein 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 Calculator Body 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 Calculator TDEE 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 Calculator Calorie 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 Calculator BMR 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 Calculator Heart 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 Calculator Ideal 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 Calculator Calorie 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 Calculator Waist 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 Calculator Lean 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 Calculator One 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 Calculator BAC 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 Calculator Sleep 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.