BMI Calculator
Body mass index with CDC adult categories and the healthy weight range for your height, plus a plain explanation of what BMI misses.
Health & Fitness Calculators
These free calculators turn your measurements into numbers you can actually plan with. Each one runs entirely in your browser, supports US and metric units, shows the formula it uses and links to the research behind it. Each tool also explains where its estimate can be wrong.
TDEE & Daily Calorie Calculator
Estimates your resting metabolism with the Mifflin-St Jeor equation and your daily calorie needs by activity level, with percentage-based targets for loss, maintenance and gain.
Macro Calculator
Splits a calorie target into protein, fat and carbohydrate grams using body-weight-based protein targets from sports nutrition research.
One-Rep Max Calculator
Estimates your 1RM from a set of 1-12 reps with the Epley and Brzycki equations and builds a training percentage table.
A suggested order
- Check where you stand with the BMI calculator, then read what BMI can't tell you.
- Find your maintenance calories with the TDEE calculator and choose a sensible deficit size if you want to lose weight.
- Turn that calorie number into food targets with the macro calculator.
- Track your strength with the one-rep max calculator as you follow a plan like the beginner 4-week workout.
Want a full plan in one place? The FitStatsHub planner on the home page combines these numbers into a seven-day meal plan and a four-week workout.
Not medical advice. This calculator gives an educational estimate only. It does not diagnose any condition or replace advice from a doctor, registered dietitian or other licensed professional. If you are pregnant, under 18, managing a medical condition or taking medication, talk to a clinician before changing how you eat or train.