BMI Calculator for Men and Women (With Waist-to-Height Ratio)
Get your BMI instantly, plus your healthy weight range, waist-to-height ratio and what your number really means for your age, build and background.
Step 1
That's all BMI needs. The next few questions make your result more accurate.
Please check your numbers. Height should be 4′7″–7′3″ (140–220 cm) and weight 70–600 lb (32–272 kg).
Step 2
The BMI formula is the same for everyone, but what your number means can differ.
Step 3
After 65, a slightly higher BMI isn't linked to the same risks.
Please enter an age between 18 and 100. For under-18s, BMI is judged on growth charts, so ask a pediatrician.
Step 4 · Optional, but recommended
Measure around your middle, halfway between your lowest rib and the top of your hip bone, after breathing out. Belly fat says more about health risk than BMI alone.
Please enter a waist between 20 and 80 inches (50–200 cm), or skip this step.
Step 5 · Optional
Health guidelines use lower BMI cut-offs for some backgrounds, because health risks start at a lower BMI.
Last step
BMI can be misleading in these cases.
Calculating your BMI…
This free BMI calculator gives you your body mass index instantly from your height and weight. Then add your waist, age and background for a more honest picture than BMI alone gives: your healthy weight range, your waist-to-height ratio, and what your number really means for someone like you. It’s for men and women 18 and over and takes under a minute.
How BMI is calculated
BMI is your weight divided by your height squared:
- Metric: BMI = weight (kg) ÷ height (m)². For example, 70 kg ÷ (1.75 m × 1.75 m) = 22.9.
- US units: BMI = 703 × weight (lb) ÷ height (in)². For example, 703 × 160 lb ÷ (68 in × 68 in) = 24.3.
The formula is the same for men and women. What changes is how much your number tells you, which is why our calculator asks a few extra questions.
BMI categories
| BMI | Category | Lower cut-offs* |
|---|---|---|
| Under 18.5 | Underweight | Under 18.5 |
| 18.5–24.9 | Healthy weight | 18.5–22.9 |
| 25–29.9 | Overweight | 23–27.4 |
| 30 and over | Obesity | 27.5 and over |
*For people of South Asian, Chinese and other Asian, Middle Eastern, Black African or African-Caribbean background, UK NICE guidance (following a WHO expert consultation) recommends these lower cut-offs, because the risk of type 2 diabetes and heart disease starts at a lower BMI. Obesity is further split into class 1 (30–34.9), class 2 (35–39.9) and class 3 (40+).
BMI chart: healthy weight for your height
Find your height to see the weight range for each category (adults, standard cut-offs).
| Height | Healthy | Overweight | Obesity |
|---|---|---|---|
| 4′10″ | 89–119 lb | 120–143 lb | 144+ lb |
| 5′0″ | 95–127 lb | 128–153 lb | 154+ lb |
| 5′2″ | 102–136 lb | 137–163 lb | 164+ lb |
| 5′4″ | 108–145 lb | 146–174 lb | 175+ lb |
| 5′6″ | 115–154 lb | 155–185 lb | 186+ lb |
| 5′8″ | 122–164 lb | 165–196 lb | 197+ lb |
| 5′10″ | 129–173 lb | 174–208 lb | 209+ lb |
| 6′0″ | 137–183 lb | 184–220 lb | 221+ lb |
| 6′2″ | 145–194 lb | 195–233 lb | 234+ lb |
| 6′4″ | 152–204 lb | 205–246 lb | 247+ lb |
Why your waist matters more than BMI
BMI can’t tell muscle from fat, and it can’t tell where your fat is. Fat around your middle (visceral fat) is the kind most linked to type 2 diabetes and heart disease. That’s why NICE now recommends measuring waist-to-height ratio alongside BMI, and a large review found it predicted heart and metabolic risk better than BMI or waist size alone.
- Under 0.5 (waist less than half your height): healthy.
- 0.5–0.59: increased risk.
- 0.6 or more: high risk.
So a 5′6″ (66-inch) person should aim for a waist under 33 inches. For the full story, including how to measure properly, read our guide to waist-to-height ratio. If you’re “normal weight” but carry fat around your middle, see sarcopenic obesity: why “skinny fat” matters and how to lose belly fat after 40.
When BMI gets it wrong
- Muscular people are often classed as overweight even with healthy body fat. It works in both directions: in a study of over 13,000 adults, a BMI of 30+ missed more than half of the people who actually had excess body fat. Our body fat calculator gives a more direct answer with just a tape measure.
- Older adults: after 65, a BMI in the “overweight” range isn’t linked to a higher risk of death, while a BMI under about 23 is. Holding on to muscle matters more than a low number.
- Pregnancy: BMI doesn’t apply. Weight-gain advice is based on your pre-pregnancy BMI.
- Children and teens: BMI is judged on age- and sex-specific growth charts, so this calculator is for adults only.
What to do with your result
If your BMI or waist is above the healthy range, you don’t need to reach “perfect” to benefit. Losing 5–10% of your body weight improves blood pressure, blood sugar and cholesterol. Start with our calorie calculator to find a sustainable deficit, and our protein calculator to protect your muscle while you lose fat. If your BMI is under 18.5, talk to your doctor. See all our free health calculators.
This calculator is for education only and isn’t medical advice or a diagnosis. Read our medical disclaimer.
Sources
- World Health Organization. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. WHO Technical Report Series 894; 2000. WHO IRIS
- WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004;363(9403):157-163. PubMed 14726171
- National Institute for Health and Care Excellence. Overweight and obesity management (NG246). nice.org.uk
- Ashwell M, Gunn P, Gibson S. Waist-to-height ratio is a better screening tool than waist circumference and BMI for adult cardiometabolic risk factors: systematic review and meta-analysis. Obes Rev. 2012;13(3):275-286. PubMed 22106927
- Romero-Corral A, et al. Accuracy of body mass index in diagnosing obesity in the adult general population. Int J Obes (Lond). 2008;32(6):959-966. PubMed 18283284
- Winter JE, et al. BMI and all-cause mortality in older adults: a meta-analysis. Am J Clin Nutr. 2014;99(4):875-890. PubMed 24452240
This article is for informational purposes only and is not medical advice. See our Medical Disclaimer before changing your exercise, diet, or supplement routine.
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Frequently asked questions
How do I calculate my BMI?
Divide your weight in kilograms by your height in meters squared. In US units, multiply your weight in pounds by 703, then divide by your height in inches squared. A 5u20328u2033, 160 lb person has a BMI of about 24.3.
What is a healthy BMI?
For most adults, a healthy BMI is 18.5 to 24.9. For people of South Asian, East Asian, Middle Eastern, Black African or African-Caribbean background, guidelines use 18.5 to 22.9, because health risks start at a lower BMI.
Is BMI different for men and women?
The formula and categories are the same, but women naturally carry more body fat than men at the same BMI. That is one reason waist-to-height ratio is a useful second check for everyone.
Is BMI accurate?
BMI is a useful quick screen, but it cannot tell muscle from fat or show where fat is stored. Muscular people can be labeled overweight, and people with a normal BMI can still carry risky belly fat. Use it alongside your waist measurement.
What is a good waist-to-height ratio?
Keep your waist to less than half your height, a ratio under 0.5. From 0.5 to 0.59 means increased health risk, and 0.6 or more means high risk.
What BMI is healthy for older adults?
After 65, a BMI slightly above 25 is not linked to a higher risk of death, while a BMI below about 23 is. For older adults, keeping muscle and strength matters more than reaching a low BMI.
How much weight do I need to lose to improve my health?
Losing just 5 to 10% of your body weight can improve blood pressure, blood sugar and cholesterol, even if you stay above the healthy BMI range.