What Is a Healthy BMI for Women? (UK)

The NHS classifies a BMI of 18.5 to 24.9 as a healthy weight for adult women. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 and above is in the obese range. Those numbers are the same across sexes — the healthy BMI range does not change with gender.

What does change is the context. Women, on average, have a higher proportion of body fat than men at the same BMI. Women also live through hormonal life stages — puberty, pregnancy, perimenopause — where weight distribution and water retention can shift within weeks. BMI is a single number; a woman’s weight story across a lifetime is not.

The healthy BMI range for women, in stones and pounds

For a quick read on whether your weight sits in the NHS healthy range, here are the upper and lower bounds for common UK women’s heights:

• 5ft 0in — roughly 7st 1lb to 9st 7lb (45–60 kg)
• 5ft 2in — roughly 7st 8lb to 10st 3lb (48–65 kg)
• 5ft 4in — roughly 8st 1lb to 10st 12lb (51–69 kg)
• 5ft 6in — roughly 8st 8lb to 11st 6lb (55–73 kg)
• 5ft 8in — roughly 9st 1lb to 12st 1lb (58–77 kg)
• 5ft 10in — roughly 9st 8lb to 12st 11lb (61–82 kg)

Use the UK BMI calculator for your exact figures, or the full BMI chart for every height.

BMI and life stages

Pregnancy

BMI is not used to assess weight during pregnancy. Your midwife will use your pre-pregnancy BMI as one input to discuss healthy weight gain, typically 10–12.5 kg over the whole pregnancy for women who started at a healthy BMI, less if you started overweight, and more if you started underweight. Do not diet during pregnancy without medical advice.

After pregnancy

Your body does not bounce back on a calendar, and it is not supposed to. Most UK women return to within a few pounds of their pre-pregnancy weight within 6–12 months. BMI is a poor tool in the first few months postpartum — fluid shifts and breast tissue changes make the number noisy. Focus on NHS postnatal advice, not on the scale.

Perimenopause and menopause

Hormonal changes around menopause tend to shift fat deposition toward the abdomen, so your BMI may stay flat while your waist-to-height ratio rises. This is one of the clearest cases for using waist measurement alongside BMI. A waist-to-height ratio above 0.5 is a useful warning signal, regardless of BMI.

Over 65

Evidence on older adults consistently shows that a BMI slightly above the NHS healthy range is not linked to higher mortality. What matters more at this age is maintaining muscle mass and avoiding unintentional weight loss. If you are over 65 and losing weight without trying to, speak to your GP.

Ethnicity and BMI

The NHS uses lower BMI thresholds for women of South Asian, Chinese, Black African and African-Caribbean family background. The healthy range becomes 18.5 to 22.9, overweight starts at 23 and obesity at 27.5. The reason is not cosmetic: these groups develop type 2 diabetes and cardiovascular disease at lower BMIs than White European populations, so the risk cut-offs are pulled earlier. This is based on NICE guidance, not opinion.

When is BMI not enough on its own?

BMI does not measure body fat directly. For women, two extra checks are worth doing:

• Waist measurement. A waist of 80 cm (31.5 inches) or more is a higher health risk for women; 88 cm (34.5 inches) or more is high. Waist-to-height ratio should stay under 0.5.
• How you feel and function. Energy levels, sleep, periods (if you have them), and mood are all meaningful indicators that the BMI number cannot capture.

What should I do if my BMI is outside the healthy range?

A BMI outside 18.5–24.9 is a prompt for a conversation, not a reason to crash diet. The NHS offers the free NHS Weight Loss Plan app (12 weeks, no cost) and the NHS Better Health service. If you have a BMI of 30 or above, ask your GP about tier-2 weight management services — these are free to access in most parts of the UK.

If your BMI is under 18.5 and you are not trying to be underweight, speak to your GP, especially if periods are irregular or absent — low body weight is a common cause.

For your BMI plus a UK-wide percentile estimate by age and sex, use the calculator on the home page.