Health calculators
Body measurements, energy, vitals, sleep and pregnancy calculators, plus an optional Health Score that combines the results you have saved.
Body measurements
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BMIBody mass index from height and weight.
Body FatUS Navy tape-measure method.
Waist-to-Hip RatioWHO risk bands from a tape measure.
Waist-to-Height RatioKeep your waist under half your height.
Ideal Body WeightThe Devine formula — a reference point, not a target.
Body Frame SizeSmall, medium or large, from a wrist measurement.
Body Surface AreaThe Mosteller formula, in square metres.
Weight Loss PercentageThe metric that accounts for where you started.
Energy & metabolism
3Heart & vitals
3Sleep & hydration
3Pregnancy & cycle
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Pregnancy Due DateNaegele's rule, from your last period.
Period CalculatorYour next few predicted periods, from your own cycle.
Ovulation CalculatorYour estimated fertile window.
Pregnancy Weight GainRecommended total gain range, by pre-pregnancy BMI.
Child Height PredictorMid-parental height method — a child's likely adult height range.
Age & wellbeing
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Health ScoreSix checks — BMI, body fat, resting heart rate, activity, sleep, hydration — weighted into one 0–100 score.
Age CalculatorExact age in years, months, weeks and days.
Alcohol Units CalculatorUnits in any drink versus the 14-unit guideline.
BAC CalculatorEstimated blood alcohol content against UK drink-drive limits.
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