Fitness & Body Calculators
Six calculators for body composition and training — where you are now, and how hard to work.
Three ways to read the same body
The BMI Calculator is fast and crude: height and weight only, blind to muscle. The Body Fat Calculator uses circumference measurements to estimate composition, which is what BMI is really trying to proxy. The Ideal Weight converts a healthy BMI range back into a weight range for your height. Read all three together — any one of them alone will mislead someone muscular, very tall or very short.
Intensity is the variable most people get wrong
Training too hard on easy days and not hard enough on hard days is the classic pattern. The Heart Rate Zones sets five zones from your maximum heart rate so you can see which one you are actually in, and the Pace Calculator converts a target race time into the per-kilometre pace you need to hold — the two together turn a vague plan into specific numbers.
Recovery is training
Adaptation happens during sleep, not during the session. The Sleep Calculator works backwards from your wake time in 90-minute cycles so you wake between cycles rather than in the middle of one, which is the difference between a rough morning and a normal one at the same total hours.
Feed the training
Once you know your intensity, set the intake: the TDEE Calculator gives your daily energy use including exercise, and the Protein Calculator sets the target that supports recovery from it.