Free Tools
Free Health & Fitness Calculators
TDEE, BMI, macros, pregnancy, sleep — based on standard medical and fitness formulas. Educational, not medical advice.
Calculators for body composition, nutrition, sleep, and pregnancy. Each uses peer-reviewed formulas (Mifflin-St Jeor, WHO BMI, Naegele's rule) — the same ones your dietitian or doctor would use. They're designed for self-education and day-to-day planning, not for replacing medical advice.
TDEE Calculator
Total Daily Energy Expenditure with macros
BMI Calculator
Body Mass Index, healthy range, ideal weight
Calorie Calculator
Daily calorie needs by goal
Macro Calculator
Protein, carbs, and fat targets
Pregnancy Due Date Calculator
LMP, conception, ultrasound — current week + trimester
Sleep Cycle Calculator
Wake refreshed — best bedtimes by 90-min cycles
Pomodoro Timer
25/5 focus intervals with notifications
Online Stopwatch & Timer
Stopwatch with laps + countdown timer
Frequently Asked Questions
Are these health calculators medically accurate?▾
They use standard formulas: Mifflin-St Jeor for BMR/TDEE (industry standard since 1990), the WHO BMI thresholds, Naegele's rule for pregnancy dating. They're educational estimates, not diagnostic tools — always confirm important decisions with a licensed healthcare provider.
TDEE vs BMR vs RMR — what's the difference?▾
BMR (Basal Metabolic Rate): calories burned at complete rest, just to keep you alive. RMR (Resting): slightly higher, includes minor activity (sitting up, eating). TDEE (Total Daily Energy Expenditure): BMR × an activity multiplier — the total you actually burn including exercise. Use TDEE for diet planning.
Is BMI useful?▾
For population-level health screening: yes. For individual athletes or anyone with above-average muscle mass: BMI overstates body fat. It's a 200-year-old formula based on height and weight only — it can't distinguish muscle from fat. Use it as one signal among many (waist circumference, body fat %, lab work).
How accurate is a sleep cycle calculator?▾
The 90-minute cycle is an average — real cycles range 70–120 minutes and shift across the night (later cycles often longer with more REM). Use the calculator as a rough guide. Consistency in sleep/wake times has a much bigger effect on rest quality than aiming for cycle boundaries.
How accurate is the pregnancy due date?▾
Naegele's rule (LMP + 280 days) is the medical standard, but only ~5% of babies are born on the exact estimated date. About 80% are born within 2 weeks before/after. Ultrasound dating in the first trimester is the most accurate when available.