BMI Calculator

Check your BMI with  our BMI Calculator

Medically reviewed by Dr. Stefan Petrov

Quickly check your BMI and see if you’re in a healthy weight range. This simple tool covers adults, children (kids’ BMI calculator), and offers a reverse BMI calculator as well. All results use recognised BMI categories from NHS and global health guidelines to help you take your next healthy step.

Find your BMI

Height

Enter numeric value. For feet, you can use 5.10 or 5'10" or 5 10.

Weight

Enter numeric value only

ℹ️ Height unit changes automatically update weight units.

Age

Years (1–120)

Your BMI Results:

BMI Score

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What Do Your BMI Results Mean?

These ranges help you understand your general health risk, but remember that BMI doesn’t tell the full story,  and everyone’s body is unique.

Underweight

BMI below 18.5: 

May signal health risks;  consider advice from a healthcare professional.

Healthy Weight

BMI 18.5–24.9: 

Linked with lower health

 risk for most adults.

Overweight

BMI 25.0–29.9:

Raises risk for type 2 diabetes, heart disease, and some cancers. Small healthy changes help.

Obesity (Class I, II, III)

BMI 30 or higher:

Higher risks; speak to your GP for support and advice.

No matter your result, taking small healthy steps can benefit your wellbeing. If you have concerns, consult your GP or use official NHS sources for tailored support.

The Official BMI Categories (Based on the NHS BMI Chart)

Once you get your result, you can use these internationally recognised weight categories to understand what your number means. These classifications are the same as those found in NHS health resources and used by the CDC.  

BMI is just one screening measure, and should be considered with other factors like waist size, physical activity, and ethnicity.

Limitations of the BMI

Use BMI alongside other health checks, like waist circumference or body fat percentage, for a clearer picture. If your results don’t match your own health or concerns, ask your GP for a personalised assessment.

Alternative Metrics & Further Health Information   

While BMI offers a useful overview, other methods provide a clearer picture of your health.

Waist Circumference

Measures abdominal fat, a strong indicator of risk for heart disease and type 2 diabetes. A larger waist size can signal higher health risks, even if your BMI is healthy.

Body Fat Percentage

Shows the proportion of fat in your body. It can be measured with skinfold calipers, bioelectrical impedance scales, or clinical scans like DEXA. These require specialist tools but give a more precise estimate.

Waist-to-Height Ratio

Calculated by dividing waist circumference by height; a ratio under 0.5 is generally healthy.

For the best health assessment, combine these methods and consult healthcare providers for personalised advice.

What Can I Do If I’m Scoring Over 30?

These ranges help you understand your general health risk, but remember that BMI doesn’t tell the full story, and everyone’s body is unique.

Consider making gradual changes to your eating habits. For NHS tips on balanced diets and healthy choices, see NHS healthy eating advice.
Increase physical activity, even short daily walks help.
Seek support from your GP or local NHS weight management services if you need extra help.
Set realistic goals; losing just a small percentage of your weight can boost health.
Many people with a BMI of 30 or above could be eligible for prescribed weight loss treatments such as Mounjaro, Wegovy, or Saxenda. Find out more about prescription treatments at Weight Fall. A healthcare professional will help check your suitability for these options.

Every positive step matters. For personalised advice and extra support, reach out to a healthcare professional or visit the official NHS website.

Frequently Asked Questions

Still have questions?

Can’t find your answer? Email us and we’ll get back to you as soon as possible!

What is a healthy BMI for adults?

What is a healthy BMI for adults? A healthy BMI range for adults, used by health bodies like the NHS, is 18.5 to 24.9 kg/m².

Is this BMI calculator NHS approved?

 No. This calculator is not officially endorsed or approved by the NHS. It uses the same BMI formula and weight categories as those used in NHS and global health guidance.

Does the BMI range change with age? 

For adults (aged 20+), healthy BMI ranges remain the same. For children, BMI is assessed using age- and sex-specific percentiles; a kids’ BMI calculator or child BMI chart is needed.

What should I do if my BMI is high? 

If your BMI is in the overweight or obesity range, it’s best to consult your GP or use NHS resources for personalised health advice and support.

Why is there a separate BMI calculator for children? 

Children’s bodies change as they grow, so healthy BMI varies by age and sex. Use a kids’ BMI calculator or child BMI chart for accurate results.

Does BMI apply to everyone? 

BMI is less accurate for athletes, older adults, and some ethnic groups. Combine BMI with other checks like waist measurement for a fuller health picture.