Body Composition
What Is a Healthy BMI? Chart, Ranges and Limits
The healthy BMI range is the same for adult women and men, but some groups face health risks at lower numbers. Here's the full chart, a healthy weight table by height, and what BMI can't tell you.
In brief: a healthy BMI for adults is 18.5 to 24.9. Below 18.5 counts as underweight, 25 to 29.9 as overweight, and 30 or more as obesity. The ranges are the same for adult women and men. The NHS uses lower thresholds for people with Black African, African-Caribbean, Middle Eastern, Chinese, South Asian or other Asian heritage. BMI is a quick screening tool, not a diagnosis.
The Healthy BMI Chart for Adults
Body mass index (BMI) compares your weight with your height. US and UK health bodies use the same adult categories, based on the World Health Organization's cut-offs:
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25–29.9 | Overweight |
| 30–39.9 | Obesity |
| 40 and above | Severe obesity |
The NIDDK, part of the US National Institutes of Health, counts severe obesity as part of the obesity category. It's listed separately here because it matters for treatment: the NHS uses a BMI of 40 or more as one of its thresholds for weight loss surgery.
Healthy BMI for Women and Men
The healthy BMI range is the same for adult women and men: 18.5 to 24.9. Neither the NHS nor the NIH uses separate adult cut-offs by sex. Whatever your sex, BMI works better alongside a waist measurement (see below).
Children and teenagers are different. For school-age children and teenagers, the WHO compares BMI with growth references for their age and sex, not with the adult categories.
Lower thresholds for some ethnic groups
A 2004 WHO expert consultation looked at evidence that many Asian populations face a higher risk of type 2 diabetes and heart disease at a lower BMI than European populations. It found the BMI at which risk rises varies between Asian populations, from about 22 to 25. The point at which risk becomes high ranged from about 26 to 31. The WHO kept its standard cut-offs as the international classification.
The NHS goes further. For people with Black African, African-Caribbean, Middle Eastern, Chinese, South Asian or other Asian heritage, it treats:
- 23 to 27.4 as overweight
- 27.5 or more as obesity
Healthy Weight by Height
This healthy BMI table shows the weight range that keeps an adult between 18.5 and 24.9 at each height. It uses the standard adult ranges:
| Height | Healthy weight range |
|---|---|
| 4 ft 10 in (147 cm) | 89–119 lb (40–54 kg) |
| 5 ft 0 in (152 cm) | 95–127 lb (43–58 kg) |
| 5 ft 2 in (157 cm) | 101–136 lb (46–62 kg) |
| 5 ft 4 in (163 cm) | 108–145 lb (49–66 kg) |
| 5 ft 6 in (168 cm) | 115–154 lb (52–70 kg) |
| 5 ft 8 in (173 cm) | 122–164 lb (55–74 kg) |
| 5 ft 10 in (178 cm) | 129–174 lb (58–79 kg) |
| 6 ft 0 in (183 cm) | 136–184 lb (62–83 kg) |
| 6 ft 2 in (188 cm) | 144–194 lb (65–88 kg) |
| 6 ft 4 in (193 cm) | 152–205 lb (69–93 kg) |
The range is wide on purpose. At any height, a healthy weight spans 30 lb (14 kg) or more. Your frame, muscle and where you carry fat all play a part. For any height not listed, the BMI calculator shows your exact range.
How to Calculate BMI
BMI is your weight divided by your height squared.
- Metric: BMI = weight in kg ÷ (height in meters × height in meters)
- Imperial: BMI = 703 × weight in lb ÷ (height in inches × height in inches)
The 703 converts pounds and inches into the same units as the metric formula.
A worked example
Someone who is 170 cm (5 ft 7 in) tall and weighs 68 kg (150 lb):
- Metric: 68 ÷ (1.70 × 1.70) = 68 ÷ 2.89 = 23.5
- Imperial: 703 × 150 ÷ (67 × 67) = 105,450 ÷ 4,489 = 23.5
A BMI of 23.5 sits in the healthy range. For someone in one of the groups the NHS uses lower thresholds for, it would count as overweight, because it's above 23.
What BMI Can't Tell You
BMI is popular because it needs only a scale and a tape measure. But it has real limits:
- It can't tell muscle from fat. The NHS notes that very muscular people can land in the overweight or obese category without carrying excess fat.
- It doesn't show where fat is. Where you carry fat matters too. The NHS advises keeping your waist to less than half your height, and suggests a waist-to-height check for anyone with a BMI under 35.
- It applies to adults only. Children, teenagers and pregnant women need different assessments.
If you want a closer look at your body composition, see how to measure body fat at home.
Limits and When to Get Advice
A BMI outside the healthy range is a reason to look more closely, not a diagnosis. A doctor can check other markers such as blood pressure, blood sugar and waist size, and look at your health history. Speak to a doctor if your BMI is under 18.5 or has changed quickly without explanation. Do the same if it's in the obese range and you'd like support to lose weight. If you're aiming to lose weight, the guide to the calorie deficit you need to lose weight explains how to do it at a safe pace.
Frequently Asked Questions
Is a BMI of 25 bad?
A BMI of 25 is the point where the overweight category starts for most adults. It's a screening signal, not a diagnosis. Your waist size, activity and other health markers matter too. If your heritage is Black African, African-Caribbean, Middle Eastern, Chinese, South Asian or other Asian, the NHS's overweight range starts lower, at 23.
What is a healthy BMI for women by age?
For adult women of any age, the standard healthy range is 18.5 to 24.9. The NHS and NIH don't change adult cut-offs with age. Age matters for children and teenagers, whose BMI is compared with growth references for their age and sex. At any adult age, a waist check adds useful context.
Why does BMI say I'm overweight when I'm muscular?
Because BMI only uses weight and height, it counts muscle the same as fat. So people with a lot of muscle can score as overweight without carrying excess fat, as the NHS points out. If that's you, a waist measurement or a body fat estimate gives a better picture than BMI alone.
Is BMI the same for men and women?
Yes. Adults use the same formula and the same categories whatever their sex. The cut-offs used by the NHS, the NIH and the WHO for adults don't change for women or men. Pair BMI with a waist check for a fuller picture.
To find your BMI and the healthy weight range for your height, use the BMI calculator.
Sources
- Calculate your BMI: BMI categories and ranges (National Heart, Lung, and Blood Institute, NIH)
- Definition and facts for adult overweight and obesity (NIDDK, NIH)
- Overweight and obesity in adults (NHS)
- Obesity and overweight fact sheet (World Health Organization)
- Appropriate body-mass index for Asian populations (WHO Expert Consultation, The Lancet, 2004)
This guide is general information, not medical advice. It was written by the CaloriePro Editorial Team from the sources above; see our editorial policy. Speak to a doctor or registered dietitian before making big changes to your diet, especially if you are pregnant, under 18, or have a medical condition.