Calculating your BMI prime is straightforward once you know the BMI Prime formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the BMI Prime Calculator.
What is BMI Prime?
The BMI Prime calculation tells you your BMI prime from a few simple inputs. The figure you are solving for here is the BMI prime.
The BMI Prime formula
The core formula is:
BMI Prime = (Weight ÷ ((Height ÷ 100) ^ 2)) ÷ 25Here is what each input means:
- Weight — a value measured in kg. Example: 70 kg.
- Height — a value measured in cm. Example: 170 cm.
How to calculate it step by step
- Write down the weight (for example, 70 kg).
- Write down the height (for example, 170 cm).
- Apply the formula above to get your BMI prime.
- Double-check the result with the BMI Prime Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Weight | 70 kg |
| Height | 170 cm |
| BMI Prime | 0.97 |
| BMI | 24.2 |
With weight of 70 kg and height of 170 cm, the BMI prime works out to 0.97.
Example 2
With weight of 140 kg and height of 170 cm, the BMI prime works out to 1.94.
| Result | Value |
|---|---|
| BMI Prime | 1.94 |
| BMI | 48.4 |
Example 3
With weight of 35 kg and height of 170 cm, the BMI prime works out to 0.48.
| Result | Value |
|---|---|
| BMI Prime | 0.48 |
| BMI | 12.1 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
- These figures are general estimates, not medical advice — check with a qualified professional before acting on them.
Prefer not to do the maths by hand? — the BMI Prime Calculator does it instantly, for free, with the formula and a worked example built in.
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