Health Calculators
◆ Body & WellbeingBMI, daily calories, pregnancy dates and ovulation timing, worked out with the standard formulas and every assumption stated plainly.
BMI Calculator
Body Mass Index in metric or imperial units, with WHO category and healthy weight range.
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Pregnancy Calculator
Work out your estimated due date from your last period, conception date, an ultrasound or an IVF transfer, then see how far along you are, your trimester and twelve milestone dates.
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Calorie Calculator
Work out your BMR and daily calorie needs from height, weight, age and activity, with targets for every weight goal, a macronutrient split and safety flags on very low intakes.
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Ovulation Calculator
Estimate ovulation by counting back from your next period, see the six-day fertile window and peak days, and plan the next six cycles with the due date for each.
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Mortgages, loans, savings and the rent versus buy decision.
Health calculators with the assumptions stated plainly
The health calculators use the same formulas a clinic would: Mifflin-St Jeor for resting energy, the standard weight over height squared for BMI, and Naegele's rule for a due date. What they add is the working, so you can see exactly which numbers produced the result.
The BMI calculator reports your category and the healthy weight range for your height in both metric and imperial units. The calorie calculator turns your height, weight, age, sex and activity level into a maintenance figure and a target for losing or gaining weight, with the macronutrient split alongside it.
The pregnancy calculator builds a full timeline from whichever date you know, whether that is a period, a conception date, a scan or an IVF transfer, and the ovulation calculator works the fertile window back from your next expected period. None of these pages is medical advice, and each one says where the estimate stops being reliable.
Frequently Asked Questions
Are these health calculators free to use?
Yes. Every health calculator here is 100% free, with no sign-up and no limits, and each one runs entirely in your browser.
Is this medical advice?
No. These pages are general information built on standard formulas and population averages. For anything that affects your health or your pregnancy, speak to a doctor or midwife.
Is anything I enter sent to a server?
No. Height, weight, dates and cycle details are calculated locally in your browser, and nothing you type is uploaded, stored or shared.
How accurate are the estimates?
They are as accurate as the formula behind them, which means they describe a population rather than an individual. Calorie needs vary by roughly 10% between people with identical measurements, and a due date is a midpoint rather than an appointment.