Health Calculators
◆ Body & WellbeingBMI, daily calories, pregnancy dates and ovulation timing, worked out with the standard formulas and every assumption stated plainly.
BMI Calculator
Enter a height and weight in metric or imperial and see the body mass index placed on the full category band, with the lower Asian and South Asian thresholds one click away.
Open calculator
Pregnancy Calculator
Estimate a due date from your last period, a conception date, a scan or an IVF transfer, then see how far along you are and when every milestone falls.
Open calculator
Calorie Calculator
Switch between the three published BMR equations, multiply by an activity factor you can actually justify, and read maintenance against loss and gain targets as proportional bars with a safe minimum built in.
Open calculator
Ovulation Calculator
Fertile window, ovulation estimate and next period date from your cycle, with a wider span when your cycles vary.
Open calculatorPlanning your money too?
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.