Calculators

These tools take your height, weight, age, and similar figures and work out a guideline tailored to you. They cover basal metabolic rate and TDEE, calories burned per exercise session, macronutrient split, body fat percentage and lean body mass, and child growth indices, plus alcohol clearance time, one-rep max, running pace, due date, menstrual cycle, and basal body temperature prediction, and working back from a wake-up time to when to go to bed. All results are guidelines from standard formulas, not medical diagnoses.

BMR Calculator (Basal Metabolic Rate)

Enter your sex, age, height, and weight to calculate your Basal Metabolic Rate (BMR) — the minimum energy your body burns at rest — using both the original 1919 and revised 1984 Harris-Benedict equations, side by side.

Free Calorie Calculator (TDEE)

Free calorie calculator. Enter your sex, age, height, weight, and activity level to calculate your Total Daily Energy Expenditure (TDEE) — your Basal Metabolic Rate multiplied by your activity level — along with target c...

Calories Burned Calculator (Free) — Estimate Energy Burned Per Workout

Free calories burned calculator. Enter the type of exercise, your weight, and duration to estimate the calories burned in that session, based on MET values. Also supports reverse mode: find the exercise time needed to hi...

Macro Calculator (Protein, Fat, Carb Split)

Enter your daily calorie target and a macro ratio (protein, fat, carbohydrate) to get the target grams for each. Choose a balanced, high-protein, or low-carb preset, or set your own custom ratio.

Body Fat Calculator (Tape Measure Only, No Scale Needed)

A free body fat calculator. Enter your height, weight and age along with your neck and waist measurements taken with a tape measure, and it estimates your body fat percentage using the US Navy method. Results from the BM...

Lean Body Mass (LBM) Calculator

Enter your weight and body fat percentage to calculate your lean body mass (LBM) and fat mass. Set a target body fat percentage to simulate the weight you would reach while keeping your lean mass unchanged.

Kaup Index & Rohrer Index Calculator (Child Growth Check)

Enter your child's age, height, and weight to calculate the Kaup Index (infants) or Rohrer Index (school-age children) automatically, matched against age-specific standards from underweight to overweight.

Alcohol Elimination Time Calculator (Free) - How Long Until It Leaves Your System & BAC

Free calculator for how long alcohol takes to leave your body and your blood alcohol content (BAC), based on drink type, amount and weight, plus drunkenness stages.

One Rep Max Calculator (1RM Calculator)

Free One Rep Max (1RM) calculator. Enter the weight and reps (1–12) you lifted to estimate your 1RM using the Epley, Brzycki, and Lombardi formulas, plus a %1RM weight chart.

Pace Calculator (Distance, Time & Pace Converter)

Free running pace calculator that converts between distance, time, and pace. Enter distance and time to get your pace, distance and pace to get your time, or time and pace to get your distance. Includes a finish time ref...

Pregnancy Due Date & Ovulation Calculator

Calculate your estimated due date, ovulation day, fertile window, and current gestational age from your last menstrual period or estimated conception date, adjusted for your cycle length.

Period Calculator (Next Period, Ovulation & PMS Predictor)

Predict your next 6 periods, ovulation days, fertile windows, and PMS timing from your recent period start dates, with average cycle length and variability calculated automatically. Everything runs in your browser and no...

BBT Chart (Basal Body Temperature) — Ovulation Estimator

Enter your daily basal body temperature to draw an automatic line chart and detect the shift from the low phase to the high phase (coverline method), showing your estimated ovulation date. Everything runs in your browser...

Sleep Calculator (90-Minute Cycle Bedtime & Wake-Up Time)

Work out the best bedtime for a wake-up time you need, or the best wake-up time if you go to bed now. Get several options aligned to 90-minute (adjustable) sleep cycles, with the healthiest range highlighted.