Calculator Suite

Free, Science-Based Fitness Calculators

15 calculators covering TDEE, BMR, macros, body composition, hydration, cutting, bulking, and recomposition. Every formula is peer-reviewed; every guide is medically reviewed.

Energy

TDEE Calculator

Total Daily Energy Expenditure with Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle. Macros, BMI, ideal weight, and weekly projections.

BMR Calculator

Basal Metabolic Rate using three peer-reviewed formulas — side-by-side comparison.

Nutrition

Macro Calculator

Goal-specific protein, carb, and fat targets for cutting, bulking, keto, and maintenance.

Protein Calculator

Daily protein in grams by body weight, training style, age, and goal.

Water Intake Calculator

Daily hydration target by body weight, activity, climate, and health factors.

Body Composition

Body Fat Calculator

Estimate body fat % using the U.S. Navy tape method or skinfold inputs.

Lean Mass / FFMI Calculator

Fat-free mass index, lean body mass, and natural muscle-building potential.

BMI Calculator

Body Mass Index with health ranges, limitations, and better alternatives.

Goals

Bulking Calculator

Lean-bulk calorie surplus, macros, and projected weekly muscle gain.

Cutting Calculator

Calorie deficit and macros for fat loss while preserving muscle.

Caloric Deficit Calculator

Safe daily deficit and projected weekly weight loss based on TDEE.

Reverse Dieting Calculator

Weekly calorie increase plan to recover metabolism after a long cut.

Specialized

TDEE for Athletes

Sport-specific calorie needs for endurance, strength, and team athletes.

TDEE for Special Populations

Adjusted calorie needs for pregnancy, teens, seniors, PCOS, and thyroid disorders.

TDEE Meal Planning

Sample meal plans by calorie target — 1500, 1800, 2000, 2500, and 3000 cal days.

Frequently Asked Questions

Which calculator should I use first?+

Start with the TDEE Calculator on the homepage. Once you know your TDEE, the macro calculator, protein calculator, cutting calculator, and bulking calculator all build on that single number.

Are these calculators free?+

Yes — every calculator is free, requires no account, and runs entirely in your browser. No personal data leaves your device.

Which formula is the most accurate?+

For the general population, Mifflin-St Jeor is the most accurate BMR equation (±10%). If you know your body fat percentage, Katch-McArdle is more accurate because it uses lean body mass directly.

How often should I recalculate?+

Recalculate every 10–15 lb (4.5–7 kg) of weight change, or any time your activity level changes meaningfully. Long cuts typically require recalculation every 4–6 weeks.