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Health Calculators

BMI, calories, macros, body fat — science-backed tools with every formula explained.

15 calculators — all free, formula included

Body Mass Index in metric or imperial — with BMI category and healthy range.

Calorie Calculator (TDEE)

Daily calorie needs using Mifflin-St Jeor — 5 activity levels, weight goal targets.

Basal Metabolic Rate — calories burned at rest, plus TDEE and weight loss target.

Macro Calculator

Daily protein, carbs, and fat targets in grams from calories and macro split.

Body Fat Calculator

Estimate body fat % using the US Navy circumference method — male and female.

Pregnancy Due Date Calculator

Calculate estimated due date from LMP, conception date, or ultrasound

Ovulation Calculator

Predict fertile window and ovulation date from last period and cycle length

Ideal Weight Calculator

Healthy weight range using Hamwi, Devine, Robinson, and Miller formulas

Pace Calculator

Running pace, speed, and finish time for 5K, 10K, half marathon, marathon

Alcohol Unit Calculator

Units in any drink from volume and ABV. Compare to UK NHS weekly limit

Sleep Calculator

Best bedtime or wake-up time using 90-minute sleep cycles

Sleep Cycle Calculator

Pick a target number of 90-minute cycles and get the matching time

How Much Sleep Do I Need?

Recommended sleep hours by age, from newborns to older adults

Power nap, NASA nap, coffee nap, or full-cycle nap wake times

Sleep Debt Calculator

See your cumulative sleep debt from the last 7 nights