Health Calculators

Calculations about the body, published only where the formula is transparent and its limits can be stated plainly. Nothing here is a diagnosis, and nothing here replaces a clinician.

• Pace CalculatorPace, speed and an exact split table for a target — metric and imperial together.
• BMI CalculatorEnter height and weight. The formula is shown, and so are its limits.
• Calorie & TDEE CalculatorTDEE is a resting figure multiplied by an activity guess. The first comes from a laboratory, the second is a convention — this page keeps them apart instead of blending them into one number.
• BMR CalculatorThe equation predicts to within 10% of a measured rate. This page shows that band, because a single figure hides it.
• Ideal Weight CalculatorThe four formulas agree closely. This page shows how narrow that agreement is next to the healthy range it hides inside.
• Body Fat CalculatorThe tape gives a percent; the method gives a band around it. This page shows both, because the band is wide enough to matter.
• Lean Body Mass CalculatorThe three formulas look like they agree. This page shows how far apart they are, and the body-fat range that gap leaves open.
• Body Surface Area CalculatorThe four formulas agree closely at an average build. This page shows the spread, and where it grows — the sizes at which the choice of formula starts to matter.
• One Rep Max CalculatorEnter a weight and the reps you managed with it. The three formulas rarely agree exactly, and the fewer the reps, the more you can trust the answer.
• Target Heart Rate CalculatorThe three formulas agree at middle age and pull apart at the edges. This page shows the spread, and treats the target zone as a band rather than a line.
• Waist-to-Height Ratio CalculatorOne rule: keep your waist under half your height. This page gives the ratio and how far your waist is from that line.
• Macro CalculatorEnter your daily calories. This page gives the macro ranges the science supports, in grams — and explains why a single “perfect” split is a preference, not a rule.
• Calories Burned CalculatorPick an activity’s MET, your weight and your minutes. This page gives both standard forms of the answer and is honest that the MET is a group average, not your number.