Health Calculators

Every calculator in this category applies a formula from the published literature to the figures you enter. None of them is a diagnosis, an assessment or a plan, and each page says which population its formula was derived from, because that is usually where the limits come from rather than the arithmetic.

Body measurements

The BMI calculator is the most asked-for and the most misread: it is a crude population screening figure that cannot distinguish muscle from fat. The body fat calculator (US Navy tape method), lean body mass and waist to hip ratio calculators give a fuller picture from measurements you can take with a tape, and the ideal weight calculator shows four different published formulas side by side precisely because they disagree.

Energy and food

The BMR calculator gives resting energy use by the Mifflin-St Jeor equation, and the daily calorie calculator scales it by activity to a total daily figure. The macro calculator, protein intake calculator and water intake calculator split that total into grams and litres. These are estimates with a real spread: two people of the same height, weight and age can differ by several hundred calories a day.

Training

The one rep max calculator estimates a maximum lift from a set you have actually done, the heart rate zone calculator gives training zones from your age or a measured maximum, and the running pace calculator converts between pace, speed and finish time for any distance.