What BMI range is considered healthy?

A BMI between 18.5 and 24.9 is considered healthy for most adults, according to WHO guidelines.

Is BMI accurate for athletes?

No. BMI does not distinguish between muscle and fat mass, so it can overestimate body fat in muscular individuals.

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How to Calculate BMI Accurately at Home

June 8, 2026

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What BMI measures

Body Mass Index (BMI) is a simple ratio of weight to height, used as a population-level screening tool rather than a diagnosis.

The formula

BMI = weight (kg) ÷ height (m)²

For imperial units, weight and height are converted to metric first, then the same formula applies.

Reading your result

BMI Range	Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 and above	Obese

Where BMI falls short

BMI does not account for muscle mass, bone density, or fat distribution. It can misclassify athletes as overweight and underestimate risk in people with low muscle mass. Use our BMI calculator as a starting point, not a diagnosis, and combine it with other health indicators.