All calculators

Choosing a calculator

Every tool here runs on one calculation engine, so the same weight gives the same BMI whichever page you are on, and moving between them keeps what you have already entered. Nothing you type is sent anywhere: the arithmetic happens in your browser, and the figures stay on your device.

If you are not sure where to start

• You know your goal and want to know how long it could take. Start with the weight-loss calculator on the front page; everything else here is a detail of that answer.
• You want one number checked, a BMI, a calorie target, a healthy weight range. Go straight to that calculator. None of them needs the others first.
• You are converting units rather than working anything out. The converters do that on their own, and every calculator takes stone and pounds directly, so you may not need one at all.

What they share

All of them take stone and pounds, kilograms or pounds, and switch between the three without you re-entering anything. All of them show a range where the underlying method only supports a range. All of them publish the formula they used and the source it came from, and say plainly where a figure has not been confirmed at source.

None of them will produce a plan for a target below the healthy BMI range, and none of them carries dosing information for any medicine.