Health & Fitness
Evidence-based health and fitness calculators: BMI, BMR, TDEE, body fat, macros, pace and more.
A1C to Glucose Converter
Convert A1C to estimated average glucose and back, in mg/dL and mmol/L, using the ADA eAG formula. Enter either value and see the match live.
BAC Calculator
Estimate your blood alcohol concentration with the Widmark formula. Enter weight, sex, drinks and hours. An estimate only, never a reason to drive.
Blood Pressure Category
Enter your systolic and diastolic numbers to find your blood pressure category using the AHA/ACC 2017 chart, from Normal to Hypertensive Crisis.
BMI Calculator
Free BMI calculator. Enter your weight and height in metric or imperial units to get your Body Mass Index and WHO weight category instantly.
BMR Calculator
Calculate your basal metabolic rate (BMR) with the Mifflin-St Jeor equation. Enter weight, height, age and sex to see calories burned at rest per day.
Body Fat Calculator
Estimate your body fat percentage with the US Navy tape method. Enter height, neck and waist (plus hip for women) to see your body fat and category.
Body Surface Area Calculator
Free body surface area calculator. Enter height and weight to get your BSA in m2 using the Mosteller, DuBois, Haycock or Gehan-George formula.
Caffeine Half-Life Calculator
See how much caffeine is left in your body after any number of hours. Enter your dose and half-life to find when you drop below a sleep-safe 50 mg.
Calorie Calculator
Estimate your daily calorie needs with the Mifflin-St Jeor equation. Get your BMR, maintenance TDEE and calorie targets to lose, maintain or gain weight.
Calorie Deficit Calculator
Find the daily calorie deficit and target for your goal. Enter maintenance calories and a weekly weight change in kg or lb to see kcal/day.
Calories Burned Calculator
Estimate calories burned by activity, body weight and time. Uses MET values for running, cycling, walking, HIIT, swimming and more.
Calories Per Serving Calculator
Split a recipe's total calories into per-serving values and break down protein, carb and fat calories. Great for meal prep and labels. Free and private.
Cat Age Calculator
Convert your cat's age to human years with the standard feline curve. Enter your cat's age and see the equivalent human age instantly. Free and private.
Cycling Power Calculator
Estimate the watts you need to ride at a given speed. Accounts for rolling resistance, air drag and gradient, with a clear power breakdown.
Dog Age Calculator
Convert your dog's age to human years. Compare the science-based epigenetic formula with the classic size-based rule and see the result instantly.
Due Date Calculator
Estimate your pregnancy due date from your last menstrual period using Naegele's rule. See how far along you are, your trimester and conception date.
eGFR Calculator
Free eGFR calculator using the race-free CKD-EPI 2021 creatinine equation. Enter creatinine, age and sex to get your eGFR and CKD stage instantly.
FFMI Calculator
Calculate your FFMI and height-normalized FFMI from weight, body fat and height. See your lean mass, fat mass and muscularity category instantly.
Heart Rate Zone Calculator
Find your five heart rate training zones from your age. Uses the 220 minus age or Tanaka formula, plus the Karvonen method if you add a resting heart rate.
Ideal Weight Calculator
Find your ideal body weight from height and sex using the Devine, Robinson, Miller and Hamwi formulas, plus a healthy weight range from BMI.
Lean Body Mass Calculator
Estimate your lean body mass from weight, height and sex with the Boer formula, or enter a measured body fat percent for a direct figure.
Macro Calculator
Split your daily calories into protein, carb and fat grams. Pick a balanced, low-carb, high-protein or keto ratio, or set your own percentages.
One Rep Max Calculator
Estimate your one rep max from a weight and reps set. Uses the Epley and Brzycki formulas and gives a percentage table for programming working sets.
Ovulation Calculator
Estimate your ovulation date and fertile window from your last period. Adjust for your cycle length to see your most fertile days and your next period.
Pace Calculator
Free running pace calculator. Enter any two of distance, finish time and pace to get the third, in min/km or min/mi, plus 5K, 10K and marathon splits.
Pregnancy Week Calculator
Find out how many weeks and days pregnant you are from your last period. See your trimester, estimated due date and days remaining.
Protein Intake Calculator
Find how much protein to eat per day from your body weight and goal. Get grams per day, grams per kg and a sensible athletic range in kg or lb.
Race Time Predictor
Predict your 5K, 10K, half marathon and marathon times from one recent race using Riegel's formula. Enter a distance and finish time to see equivalents.
Running Pace Calculator
Work out your running pace per km and per mile plus speed in km/h and mph. Enter a distance and finish time to see splits and predict race times.
Running Pace Splits Calculator
Plan even race splits for a goal finish time. See pace per km or mile and the cumulative clock time at every mark for a 5K, 10K, half or marathon.
Sleep Calculator
Find the best time to sleep or wake up using 90-minute sleep cycles. Enter a wake-up time for ideal bedtimes, or a bedtime for wake-up times. Free.
Sleep Cycle Calculator
Find the best time to go to bed or wake up. Plans around 90-minute sleep cycles so you wake between cycles feeling rested, not groggy. Free and private.
Steps to Distance Calculator
Convert your step count into miles and kilometres. Enter steps and a stride length, or estimate the stride from your height and walking or running.
Stride Length Calculator
Estimate your walking and running stride length from your height. Get stride and step length in inches and cm, plus how many steps make a mile.
Swim Pace Calculator
Calculate your swim pace per 100 metres and average speed. Enter the distance you swam and your time to see your pace and metres per second.
TDEE Calculator
Calculate your TDEE and daily calorie needs. Enter weight, height, age, sex and activity to see maintenance, cutting and bulking targets.
Treadmill Pace Converter
Convert treadmill speed in mph to running pace per mile and per km, or turn a goal pace into a treadmill speed. See the matching km/h speed too.
VO2 Max Calculator
Estimate your VO2 max from a Cooper run, resting heart rate, or Rockport one-mile walk. See your fitness category by age and sex. Free and private.
Waist to Hip Ratio Calculator
Free waist to hip ratio calculator. Enter your waist and hip measurements to get your WHR and the WHO health risk category for men and women.
Waist-to-Height Ratio Calculator
Calculate your waist-to-height ratio, a strong marker of central fat. Enter waist and height in cm or inches to see your ratio and category. Free and private.
Water Intake Calculator
Find how much water to drink each day. Enter your weight and exercise time to get a personalized target in liters, ounces and cups.
Wilks Calculator
Calculate your Wilks score from your total and bodyweight. Uses the original Wilks formula so lifters of any size can compare strength fairly.