"What should I weigh for my height?" is one of the most common questions UK adults type into Google. There's no single perfect number — but there is a healthy range, and the NHS uses a clear, evidence-based system to define it.
The NHS approach: BMI 18.5 to 24.9
The NHS defines a "healthy weight" as having a BMI between 18.5 and 24.9. From that, you can work backwards to a healthy weight range for any height.
The formula:
Weight in kg = BMI × (height in metres)²
Ideal weight ranges by height (UK)
Women
| Height | Healthy weight range |
|---|---|
| 4'11" (150cm) | 6st 7lb – 8st 11lb (42–56kg) |
| 5'0" (152cm) | 6st 9lb – 9st 0lb (43–58kg) |
| 5'1" (155cm) | 6st 13lb – 9st 4lb (44–60kg) |
| 5'2" (157cm) | 7st 2lb – 9st 7lb (45–61kg) |
| 5'3" (160cm) | 7st 6lb – 9st 12lb (47–63kg) |
| 5'4" (163cm) | 7st 10lb – 10st 3lb (49–65kg) |
| 5'5" (165cm) | 7st 13lb – 10st 7lb (50–67kg) |
| 5'6" (168cm) | 8st 3lb – 10st 12lb (52–69kg) |
| 5'7" (170cm) | 8st 5lb – 11st 2lb (53–71kg) |
| 5'8" (173cm) | 8st 9lb – 11st 7lb (55–73kg) |
| 5'9" (175cm) | 8st 12lb – 11st 11lb (56–75kg) |
| 5'10" (178cm) | 9st 2lb – 12st 2lb (58–77kg) |
| 5'11" (180cm) | 9st 6lb – 12st 7lb (60–79kg) |
Men
| Height | Healthy weight range |
|---|---|
| 5'4" (163cm) | 7st 10lb – 10st 3lb (49–65kg) |
| 5'5" (165cm) | 7st 13lb – 10st 7lb (50–67kg) |
| 5'6" (168cm) | 8st 3lb – 10st 12lb (52–69kg) |
| 5'7" (170cm) | 8st 5lb – 11st 2lb (53–71kg) |
| 5'8" (173cm) | 8st 9lb – 11st 7lb (55–73kg) |
| 5'9" (175cm) | 8st 12lb – 11st 11lb (56–75kg) |
| 5'10" (178cm) | 9st 2lb – 12st 2lb (58–77kg) |
| 5'11" (180cm) | 9st 6lb – 12st 7lb (60–79kg) |
| 6'0" (183cm) | 9st 11lb – 12st 13lb (62–82kg) |
| 6'1" (185cm) | 10st 1lb – 13st 5lb (64–84kg) |
| 6'2" (188cm) | 10st 5lb – 13st 11lb (66–87kg) |
| 6'3" (191cm) | 10st 10lb – 14st 3lb (68–90kg) |
| 6'4" (193cm) | 11st 0lb – 14st 9lb (70–93kg) |
(Tables apply to non-pregnant adults aged 18+. Men and women share the same ranges in the NHS BMI system.)
The ethnicity adjustment
The NHS recognises that for adults of South Asian, Chinese, Black African, Black Caribbean and Middle Eastern heritage, health risks rise at lower BMIs. For these groups, the upper end of "healthy" is BMI 23 instead of 24.9.
For a 5'6" (168cm) adult of South Asian heritage, this means the ideal weight ceiling drops from 10st 12lb to about 10st 1lb (64kg).
Other formulas you'll see online
Devine formula (1974)
- Men: 50 kg + 2.3 kg per inch over 5 feet
- Women: 45.5 kg + 2.3 kg per inch over 5 feet
Originally designed for medication dosing, not health. Tends to give a single number rather than a range.
Robinson formula (1983)
- Men: 52 kg + 1.9 kg per inch over 5 feet
- Women: 49 kg + 1.7 kg per inch over 5 feet
Hamwi formula (1964)
- Men: 48 kg + 2.7 kg per inch over 5 feet
- Women: 45.5 kg + 2.2 kg per inch over 5 feet
These older formulas are still used clinically but tend to give lower target weights than the modern NHS BMI range. For most people, the NHS BMI range is the more appropriate reference.
What if I'm above my ideal range?
Don't panic. The first step is working out the gap. The NHS recommends losing weight at 1–2 lb per week through a 500–600 kcal daily deficit.
If you're 2 stone above your range, that's roughly 14 weeks of steady loss — three to four months. Faster than that usually doesn't last.
What about muscle and athleticism?
If you lift weights or have a naturally muscular build, you may be "above your ideal weight" by BMI but still very healthy. Muscle is denser than fat — a 5'8" rugby player might weigh 14 stone with low body fat and excellent fitness.
For these cases, body fat percentage or waist measurement is more useful than weight or BMI alone.
Should I aim for the middle of the range?
Generally, aiming for the middle of the BMI range (around BMI 22) is a sensible target for most adults. There's nothing magical about a specific number — anywhere in 18.5–24.9 is medically considered healthy, and trying to hit a precise target weight often does more harm than good for mental health.
The bottom line
For most UK adults, "ideal weight" is a range, not a single number. Use the table above (or the calculator) to find your range, aim for the middle if you want a target, and combine weight with a waist measurement for a fuller picture. If you have any concerns, your GP can give personalised advice.
Sources: NHS BMI guidance, NICE clinical guideline CG189, NHS Better Health, Devine/Robinson/Hamwi formulas (cited for context only). For individual advice, consult your GP.