NHS-aligned · Ethnicity-adjusted
BMI Calculator
Calculate your Body Mass Index using UK measurements. Includes NHS-aligned thresholds and ethnicity-adjusted ranges.
What is a healthy BMI?
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obese (Class I) |
| 35.0 – 39.9 | Obese (Class II) |
| 40.0+ | Obese (Class III) |
BMI limitations
- BMI doesn't distinguish between muscle and fat — muscular individuals may have a higher BMI without being overweight
- Waist circumference is a better indicator of central obesity risk
- Ethnicity affects risk thresholds — South Asian and Black African populations face higher risk at lower BMI levels
- BMI is less accurate for children, elderly adults, and pregnant women
BMI by age and gender
BMI thresholds are the same for adults of all ages and genders. However, body composition changes with age, and women typically carry more body fat at the same BMI. The NHS uses the same ranges for all adults aged 18+.
| Group | Healthy BMI | Notes |
|---|---|---|
| Adults 18–65 | 18.5 – 24.9 | Standard NHS range |
| Adults 65+ | 23 – 30 | Slightly higher range may be protective |
| South Asian adults | 18.5 – 22.9 | Overweight threshold lowered to BMI 23 |
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
Get Started →Plans from £149.99/month
AdNew here?
£30OFF
On All Weight Loss Orders Use Code: FIRST30