Nutrition Calculators
Three free, evidence-based tools — for calorie needs, BMI, and optimal macronutrient split. No sign-up, no ads.
Calorie Calculator
Basal metabolic rate (BMR), total daily expenditure (TDEE), and calorie target — based on the Mifflin-St Jeor equation.
- ·BMR and TDEE
- ·Activity-level adjustment
- ·Recommended macro split
BMI Calculator
Body Mass Index with WHO category classification and a visual scale.
- ·BMI value and category
- ·Visual classification
- ·Notes on what BMI does and doesn't tell
Macro Calculator
Optimal split between protein, carbs, and fat — with presets for balanced, high-protein, low-carb, and keto.
- ·Presets for every goal
- ·Grams and calories per macro
- ·Adapted to TDEE and goal
How our calculators work
All calculators run on established peer-reviewed equations — not marketing approximations. The calorie calculator uses the Mifflin-St Jeor formula, considered the most accurate non-lab estimate of basal metabolic rate in independent comparison studies. The BMI calculator uses the official WHO classification. The macro calculator sets protein first (1.6–2.2 g/kg), then fat, and fills the remaining calories with carbs — the order that has become the standard in sports nutrition research.
Think of these tools as the starting point, not the final verdict. Calculate your numbers, eat at that target for two weeks, compare your weekly-average weight change to the expectation, then adjust. Our TDEE guide walks through the logic in detail.