Calculate∑ What your result means
BMI is a simple screening measure the NHS uses to categorise weight relative to height into underweight, healthy weight, overweight and obese bands.
NHS BMI Calculator
Calculate your Body Mass Index using the NHS's standard BMI bands.
Your details
kg
cm
◇ Your values stay in this browser.
Verified for 2026-27Methodology 2026-27.1 · reviewed 2026-08-08 · review by 2027-03-01
Was this result useful?
Compare scenarios
Change weight to see the effect on your result.
Understand your result
Clear context for the values above.
Weight
Weight is included so you can interpret this estimate and make a better-informed comparison.
Height
Height is included so you can interpret this estimate and make a better-informed comparison.
Your BMI
Your BMI is included so you can interpret this estimate and make a better-informed comparison.
Healthy-weight range minimum
Healthy-weight range minimum is included so you can interpret this estimate and make a better-informed comparison.
How to use this calculator
- 1Enter your current weight, height.
- 2Review the headline your bmi and the supporting figures beside it.
- 3Change one input at a time to see which assumption has the biggest effect.
- 4Confirm current UK rates and thresholds with an official source before acting.
Explore this calculator
What your result means →The headline your bmi is based on the inputs currently shown above.Key terms explained →Review the assumptions, applicable rules, timing and real-world fees before making a decision.How to use this calculator →Enter your figures, review the live result, compare scenarios, then save or print your estimate.The calculation formula →The calculation follows the standard relationship between the displayed inputs. Results update whenever an input changes.Worked example →Using the current values produces 26.0.Assumptions and limitations →Review the assumptions, applicable rules, timing and real-world fees before making a decision.Costs or factors not included →Review the assumptions, applicable rules, timing and real-world fees before making a decision.Frequently asked questions →How accurate is this estimate? What should I check before relying on it? Can I save or share the result?
▦ How this calculator works
BMI is calculated as weight in kilograms divided by height in metres squared. The NHS generally classes a BMI under 18.5 as underweight, 18.5–24.9 as healthy weight, 25–29.9 as overweight, and 30 or above as obese — your result shows which of these bands your BMI falls into.
◇ Assumptions and what's not included
BMI doesn't distinguish fat from muscle mass and can be misleading for athletes, and NHS guidance notes that BMI thresholds for increased health risk are lower for some Asian, Black and other minority ethnic groups.
▤ What to do next
Use BMI as one starting indicator alongside waist measurement and overall health, and speak with a GP or practice nurse for a fuller assessment rather than relying on BMI alone.
UK-specific contextFigures use GBP and current published rates and thresholds.
Reviewed for clarityUpdated 3 August 2026.
ImportantFor planning and educational use — not tax, legal or financial advice.
Your privacy mattersInputs stay in your browser.
Frequently asked questions
Is BMI accurate for muscular people?+
No, BMI doesn't distinguish muscle from fat, so very muscular individuals can show a higher BMI without carrying excess fat.
Does the NHS use the same bands for everyone?+
NHS guidance recognises that health risk at a given BMI can start at a lower threshold for some Asian, Black and other minority ethnic groups compared with the standard bands used here.
Is BMI suitable for children?+
No, children and teenagers need age- and sex-specific BMI centile charts rather than the adult bands used in this calculator.
What should I do if my BMI is outside the healthy range?+
Speak with a GP or practice nurse, who can assess your overall health picture rather than relying on BMI as a single number.
Official references
Rules and thresholds used by this calculator are labelled for 2026–27 or formula-labelled period. Review the primary guidance before making a filing, borrowing, benefit or investment decision.
Last source review: 3 August 2026. Calculator results are estimates and may exclude circumstances described in the methodology.