Health calculators
A number on its own tells you almost nothing.
Most calculators hand you a figure and leave. Ours show you the whole scale — where your result sits, which band it falls in, and how far it is from the next one. Then they tell you what the measurement can't see.
Five calculators
Each one runs entirely in your browser. Nothing you type is sent anywhere.
How these are built
Short version: the formula is always named, and the limits always stated.
Every equation used on this site is a published one, and every page names it. Where an equation has known failure modes — and they all do — the page says so rather than burying it. BMI can't tell muscle from fat. Calorie equations miss individual metabolism by around a tenth in either direction. Sleep cycles vary by half an hour between people.
That's not a disclaimer bolted on at the end. It's most of the value. A person who knows their BMI is 27 and understands why that might mean very little for them is better informed than one who knows only the number.
Nothing you enter leaves your device. There are no accounts, no saved results, and no data sent to a server — the arithmetic happens in JavaScript on the page in front of you.