Health & Fitness

Calculate your body mass index from height and weight in metric or US units, see your WHO weight category and the healthy weight range for your height.

Estimate your daily calorie needs (TDEE) and resting metabolic rate (BMR) with the Mifflin-St Jeor equation, plus targets to lose or gain weight.

Estimate body fat percentage from your neck, waist (and hip) measurements and height with the US Navy tape method, plus fat and lean mass.

Split your daily calories into protein, carbohydrate and fat grams — balanced, high-protein, low-carb or keto — or set your own percentages.

Find how much protein you need per day based on body weight and goal — general health, endurance, building muscle or losing fat.

Estimate how much water to drink each day from your body weight and exercise, in litres, ounces and glasses.

Estimate ideal body weight from height and sex with the Devine, Robinson, Miller and Hamwi formulas — alongside the healthy BMI weight range.

Calculate your waist-to-hip and waist-to-height ratios — simple measures of abdominal fat linked to heart and metabolic health risk.

Estimate lean body mass with the Boer formula (or from your body fat %) and your fat-free mass index (FFMI), normalized to 1.8 m.

Estimate your one-rep max from the weight and reps you lifted with the Epley, Brzycki and Lombardi formulas, plus a percentage chart for programming.

Work out which plates to load on each side of the barbell to hit a target weight, in kilograms or pounds, with your available plates.

Compare powerlifting strength across body weights with the DOTS and original Wilks formulas from your total and body weight.

Calculate running pace, finish time or distance — per km or per mile — with speed in km/h and mph and splits for the whole race.

Predict your 5K, 10K, half marathon and marathon times from a recent race result using Riegel's formula.

Estimate your VO2 max (aerobic fitness) from a 12-minute Cooper run test or from your resting and maximum heart rate.

Calculate your five heart rate training zones and target heart rate with the Karvonen (heart rate reserve) method or a simple % of max.

Estimate calories burned walking, running, cycling, swimming, lifting and 20+ other activities from your weight and the time spent.

Convert a step count into miles or kilometres using your height (or a measured stride length), plus a rough calorie estimate.

Calculate bike speed from cadence and gearing (chainring, cog, wheel size), plus gear ratio, gear inches and development.

Calculate your swim pace per 100 m or 100 yd from distance and time — and predict times for other swim distances.

Find the best times to go to bed or wake up so you wake between 90-minute sleep cycles and feel less groggy.

Add up your daily caffeine from coffee, tea, soda and energy drinks and compare it with the 400 mg/day guideline for healthy adults.

Estimate blood alcohol concentration from drinks, body weight, sex and time with the Widmark formula — for education only, never to decide whether to drive.

Classify a blood pressure reading as normal, elevated, stage 1 or stage 2 hypertension, or a hypertensive crisis using the AHA/ACC guidelines.

Convert blood glucose between mg/dL and mmol/L, and HbA1c to estimated average glucose (eAG) — with the ADA diagnostic ranges.

Calculate your total-to-HDL cholesterol ratio, LDL-to-HDL ratio and non-HDL cholesterol from a lipid panel, in mg/dL or mmol/L.

See how much smoking or vaping costs per week, year and decade — and what that money would grow to if you quit and invested it.

Understand your glasses prescription — SPH, CYL, AXIS and ADD — including whether you're short- or long-sighted, and convert between plus and minus cylinder.

Find your recommended daily fiber intake from your age, sex or calorie intake, based on the US Dietary Guidelines (14 g per 1,000 kcal).

See which blood types can give red cells and plasma to which — ABO and Rh compatibility for transfusions, explained simply.

Guided breathing with an animated circle — box breathing, 4-7-8 relaxation, coherent breathing and more — to calm down, focus or fall asleep.

Track intermittent fasts — 16:8, 18:6, 20:4, OMAD or custom — with a live timer, eating-window times, fasting stages and a history saved in your browser.

A HIIT and Tabata interval timer with work/rest rounds, sets, a warm-up and audible countdown beeps — for workouts, circuits and boxing rounds.

Test your reaction time — click as soon as the screen turns green. See your average over 5 tries and how you compare with typical human reaction times.