Health
Wellness numbers you actually understand
BMI, BMR, calorie targets, body composition — formulas from peer-reviewed research presented with metric + imperial side by side. For estimation only; consult a clinician for medical decisions.
7 tools
- BMI CalculatorFree BMI calculator with metric + imperial units. Shows category from underweight to obese class III. For estimation only.
- BMR CalculatorBasal Metabolic Rate calculator using the Mifflin–St Jeor equation. Daily calorie burn at complete rest.
- Calorie & TDEE CalculatorDaily calorie target calculator. BMR (Mifflin–St Jeor) × activity factor × goal adjustment. Returns TDEE and weight goal calories.
- Body Fat Percentage CalculatorUS Navy method body fat % from waist, neck, height (and hip for women). Quick estimate without calipers.
- Running Pace CalculatorCompute pace from distance + time, or predict time from pace + distance. Min/km, min/mile, common race distances.
- Sleep CalculatorOptimal bedtimes for waking refreshed. Based on 90-minute REM cycles + 14-minute fall-asleep average.
- Pregnancy Due Date CalculatorEstimated due date from last menstrual period (Naegele's rule, 40 weeks). For information only — not medical advice.
Choosing between these tools
Every number here comes from a published formula, and each tool names the one it uses so you can check it. BMR uses Mifflin-St Jeor; body fat uses the US Navy circumference method; TDEE is BMR multiplied by an activity factor.
Those formulas were fitted to populations, not to you. BMI in particular describes a ratio of mass to height and cannot distinguish muscle from fat, which is why a lean athlete and a sedentary person of the same build can share a reading. Circumference-based body fat is better on that specific point and still carries several percentage points of error. Read the outputs as a starting range to discuss, not a diagnosis.
The pace, sleep and pregnancy tools are scheduling arithmetic rather than clinical estimates — a due date is the standard 280 days from the last menstrual period, which is a convention, not a prediction. For anything that affects treatment, medication or a health decision, talk to a clinician. Nothing you enter leaves your browser.