Health calculators
Eight free tools for body composition, daily needs and timing. Metric or imperial, with a plain account of what each measure misses.
All health calculators
BMI calculator
Body mass index on a color-coded scale.
Calorie calculator
BMR, TDEE and a macro split.
Age calculator
Exact age in years, months and days.
Water intake
Daily target for your weight and climate.
Sleep calculator
Bedtimes that land between cycles.
Body fat percentage
US Navy method estimate.
Ideal weight
Healthy range across four formulas.
Due date calculator
Estimated due date and current week.
No tools in this group.
What these tools do
Eight calculators covering common health and body composition questions. Each one states which formula it uses and each one is honest about where that formula fails, because every measure here has groups it describes badly.
Start with the right tool
Body composition. BMI compares weight to height and is the quickest screen, though it cannot distinguish muscle from fat. Body fat percentage separates the two using tape measurements. Ideal weight shows four different formulas so you can see how much they disagree.
Daily needs. The calorie calculator gives your resting metabolic rate, your maintenance level and a target for your goal. Water intake scales a daily fluid target to your weight, activity and climate.
Dates and timing. The age calculator handles leap years and uneven months correctly. The sleep calculator works backward from your alarm in ninety minute cycles. The due date calculator estimates a delivery date and shows the milestones along the way.
Metric and imperial
Every tool here takes centimeters and kilograms or feet, inches and pounds. Switching converts what you have already typed rather than clearing it and the calculation runs in metric internally either way, so both paths give the same answer.
None of this is medical advice. These are screening estimates built on population averages. They cannot account for your medical history, medication, body composition or ancestry and several are known to be unreliable for specific groups. Speak to a doctor or registered dietitian before acting on any result.
Finance calculators
Loans, investments, margins and payroll dates, all showing their working.