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BMI calculator.
Body mass index is your weight against your height, and nothing else. It is a useful population statistic and a blunt instrument for any one person. Here is your number, and what it is actually worth.
What BMI is, and what it is not
The sum. Your weight in kilograms divided by your height in metres squared. That is the whole calculation. The ranges below 18.5, 18.5 to 25, 25 to 30 and above 30 are the World Health Organization classification, which is the same set every other BMI tool quotes.
It cannot tell muscle from fat. This is the limitation that matters most here, because if you lift, BMI will read you as overweight while you are in good shape. A 90 kg rugby player and a 90 kg sedentary man of the same height get the same number. The formula only knows your mass. If your BMI says overweight and your waist, your lifts and your photographs disagree, believe the other three.
Where it is still useful. As a rough starting point, and for tracking a large change in yourself over time. It is a screening tool designed for populations, not a diagnosis, and it was never meant to be applied to an individual on its own. It also says nothing about where fat sits, which is the part that actually carries health risk.
Better numbers to use. Your waist measurement, your body fat percentage if you can measure it honestly, and the direction all of them are travelling. For deciding what to actually eat, the TDEE calculator gives you a daily figure that BMI cannot, and the goal weight calculator turns a target into a date.
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This is an estimate and a starting point, not medical advice. Every equation of this kind is a population average, so your real burn can sit a few hundred kcal either side of it. Track for two or three weeks and adjust to what actually happens on the scales. If you are pregnant, managing a health condition or unsure, speak to a doctor or dietitian first.
There is no account here and no tracking cookie, so nothing you enter is saved to a profile or tied to you. The sums run on our server, and your answers travel in the page address, which is what makes a result shareable. Treat a link you send as carrying those numbers with it.
Now log against it
A number is only useful if you can hit it. Whey to Go tracks food and training against targets like these, on your device, with no account and nothing sold.