Science-Backed Fitness Calculators
Our collection of free health and composition calculators runs 100% on your device. No tracking cookies, no accounts, no server logging. Just clean utilities backed by peer-reviewed research.
TDEE Calculator
Calculate your Total Daily Energy Expenditure. The most critical baseline metric for calorie planning.
Calorie Target
Find your exact daily calorie budget to lose fat, build muscle, or maintain weight.
Macro Split
Split your daily calories into custom protein, carbohydrate, and fat gram targets.
BMI Calculator
Standard Body Mass Index calculation. Instant weight-to-height screening results.
Body Fat %
Estimate your body fat percentage using the US Navy method. More accurate than BMI alone.
Calorie Deficit Planner
Interactive 12-week weight loss timeline and calorie deficit projection tool.
BMR Calculator
Find your Basal Metabolic Rate — the calories your body burns to survive at complete rest.
Biological Fitness Age
Calculate your biological fitness age based on the landmark HUNT physical study.
1 Rep Max
Estimate your one rep max (1RM) using Epley, Brzycki, Lander, and Lombardi formulas.
Sleep Cycles
Calculate your sleep cycles, ideal bedtimes, and wake-up times to avoid grogginess.
Sleep Debt
Calculate your accumulated sleep deficit and get a progressive recovery plan.
Ideal Weight
Establish your healthy weight target based on 5 different medical and clinical formulas.
Protein Intake
Calculate daily protein targets in grams based on activity and lean body mass.
Water Intake
Calculate baseline water needs adjusted for exercise duration to maintain optimal hydration.
Heart Rate Zones
Identify target warm-up, fat-burn, aerobic, threshold, and peak cardio training zones.
Lean Body Mass
Determine your metabolically active mass (organs, bones, muscles) relative to fat.
Running Pace Calculator
Calculate race splits, distance paces, and marathon finish predictions.
Army Body Fat Calculator
Official U.S. Army circumference body composition standard calculator.