BMI Calculator: NHS UK Guidelines
A BMI of 18.5 to 24.9 is considered healthy for most adults by the NHS. BMI divides your weight in kilograms by your height in metres squared. For a 75kg person at 175cm, that equals 24.5, which is healthy weight. Use this calculator to check where you fall and see your ideal weight range.
Source: NHS body mass index guidance. Supports the NHS weight category boundaries.
Calculator
Your BMI
24.5
Healthy Weight
Healthy Weight Range
56.7kg to 76.3kg
125 to 168 lbs
Category
Healthy Weight
NHS Classification
Your BMI is within the healthy range (18.5 to 24.9). Maintain this through balanced nutrition and regular physical activity.
BMI doesn't distinguish between muscle and fat, or account for body composition, ethnicity, or age. It's a screening tool, not a diagnosis. Waist circumference may be a better indicator of health risk.
These insights are generated based on your inputs and general UK financial guidelines. They do not constitute personal financial advice. Always consult a qualified accountant or FCA-regulated adviser before making financial decisions.
What this calculation assumes
BMI is weight in kilograms divided by height in metres squared. Category boundaries follow NHS guidance.
- BMI does not distinguish muscle from fat and is a screening indicator only
- It is not a diagnosis and does not replace advice from a clinician
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How BMI Calculator: NHS UK Guidelines Works
How BMI is calculated
BMI = weight (kg) ÷ height (m)². It's a simple screening tool used by the NHS and GPs to classify weight status. It does not measure body fat directly - a muscular person may have a high BMI without excess fat.
NHS BMI categories
Under 18.5 = Underweight. 18.5 to 24.9 = Healthy weight. 25 to 29.9 = Overweight. 30 to 34.9 = Obese (Class I). 35 to 39.9 = Obese (Class II). 40+ = Severely obese (Class III).
Limitations of BMI
BMI doesn't distinguish between muscle and fat mass. Athletes may be classed as overweight despite low body fat. Different thresholds apply for South Asian, Chinese, and other ethnicities - the NHS recommends a lower healthy BMI range (23 instead of 25) for these groups.
Frequently Asked Questions
The NHS defines a healthy BMI as 18.5 to 24.9 for most adults. For South Asian, Chinese, and other Asian backgrounds, a healthy BMI is considered to be 18.5 to 23, with overweight starting at 23 and obese at 27.5.
BMI is a useful population-level screening tool but has limitations for individuals. It doesn't account for muscle mass, bone density, fat distribution, or ethnicity. A fit athlete may have a high BMI, while someone with low muscle mass might have a 'healthy' BMI but still be at health risk.
Healthy weight depends on your height. Use this calculator to find your healthy weight range. The calculator shows both kg and lbs equivalents for your specific height.
Yes, particularly if you have high muscle mass. However, BMI is a useful first indicator and the NHS uses it alongside waist circumference, blood pressure, and other measures to assess health risk.
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Sources and method
- NHS body mass index guidance (NHS). Supports: The NHS weight category boundaries. United Kingdom, Current NHS guidance.
Method: Body mass index formula.
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Further reading
Background references used while writing this page. The sources behind the calculated figures are listed above.
Disclaimer: This calculator provides estimates based on standard HMRC rates for 2026/27. Results may vary based on individual circumstances. This is not financial advice. Always consult a qualified accountant or CIMA-qualified financial adviser for personal tax matters.