Weight loss math, made simple.
Six free calculators — TDEE, BMI, calorie deficit, protein, and maintenance — built on the same peer-reviewed formulas dietitians use. Get your numbers in under 60 seconds.
Start with TDEE How to track caloriesPick your calculator
Each tool shows its formula, sources, and a worked example — so you understand the number, not just trust it.
TDEE Calculator
Total Daily Energy Expenditure — the foundation of every diet plan.
Open calculatorBMI Calculator
Body Mass Index with WHO category ranges and healthy weight bands.
Open calculatorCalorie Deficit Calculator
Find the daily intake that matches your weight-loss timeline.
Open calculatorProtein Calculator
Daily protein targets backed by ISSN position-stand evidence.
Open calculatorMaintenance Calories
How many calories you need to hold your weight steady.
Open calculatorHow to Track Calories
A practical, no-BS guide to logging food accurately.
Open calculatorBuilt on the formulas dietitians trust
We use the Mifflin–St Jeor equation for BMR (more accurate than Harris–Benedict for modern body compositions), standard PAL multipliers from the WHO/FAO/UNU report, and protein recommendations from the International Society of Sports Nutrition.
Mifflin–St Jeor
The most accurate BMR equation for healthy adults, validated across multiple populations.
Read the formulaActivity multipliers
Why a "1.55" multiplier might be wrong for you, and how to pick honestly.
Pick your PALProtein requirements
Why 0.8 g/kg is a floor, not a target — and how much you actually need.
See the evidence