Free health and fitness calculators that run in your browser
Fast health and fitness calculators for body fat, ideal weight, macros, hydration, one-rep max, running pace, pregnancy and more — 100% in your browser with no uploads or signup.
Body Fat Calculator
Estimate body fat percentage with the US Navy tape method for men and women.
Ideal Weight Calculator
Find ideal body weight with Devine, Robinson, Miller and Hamwi formulas plus a healthy BMI range.
Macro Calculator
Turn TDEE into daily protein, carb and fat grams for cutting, maintaining or bulking.
Water Intake Calculator
Estimate daily water needs from body weight, activity and climate in ml and oz.
One Rep Max Calculator
Estimate your 1RM from weight and reps with Epley and Brzycki plus a percentage table.
Running Pace Calculator
Calculate running pace, predict other race distances and convert pace to speed.
Due Date Calculator
Estimate a pregnancy due date from the last period or conception with current week and trimester.
Ovulation Calculator
Find your fertile window and estimated ovulation day from cycle length and last period.
Blood Alcohol Calculator
Estimate blood alcohol content with the Widmark formula from drinks, weight, sex and time.
Calorie Deficit Calculator
Find the daily calorie target to reach a goal weight by a chosen date.
Sleep Calculator
Find the best bedtime or wake-up time using 90-minute sleep cycles and fall-asleep time.
TDEE & BMR Calculator
Calculate BMR (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) and TDEE with calorie targets.
Heart Rate Zones Calculator
Find max heart rate and five training zones by % of max or Karvonen reserve.
Private health and fitness calculators
Every tool on Health Tools runs entirely on your device using JavaScript. Your measurements are never uploaded to a server, which makes every estimate instant and completely private. There's no signup, no profile and no tracking of your body data.
Plan training and nutrition with the macro calculator, estimate body fat percentage, check your one-rep max, dial in your running pace or track a pregnancy with the due date calculator. Pick a tool above and start in seconds — results stay on your device.
Health Tools is for general information and educational use only. It does not provide medical advice, diagnosis or treatment. Always consult a qualified healthcare professional for personal health decisions.