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.
BMI Calculator
Free BMI calculator with metric + imperial units. Shows category from underweight to obese class III. For estimation only.
BMR Calculator
Basal Metabolic Rate calculator using the Mifflin–St Jeor equation. Daily calorie burn at complete rest.
Calorie & TDEE Calculator
Daily calorie target calculator. BMR (Mifflin–St Jeor) × activity factor × goal adjustment. Returns TDEE and weight goal calories.
Body Fat Percentage Calculator
US Navy method body fat % from waist, neck, height (and hip for women). Quick estimate without calipers.
Running Pace Calculator
Compute pace from distance + time, or predict time from pace + distance. Min/km, min/mile, common race distances.
Sleep Calculator
Optimal bedtimes for waking refreshed. Based on 90-minute REM cycles + 14-minute fall-asleep average.
Pregnancy Due Date Calculator
Estimated 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.