What is a healthy BMI range?

According to the NHS, a healthy BMI is between 18.5 and 24.9. A BMI below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese.

Is BMI accurate for everyone?

BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat, so very muscular people may have a high BMI despite being healthy. It may also be less accurate for older adults, pregnant women, and certain ethnic groups.

BMI Calculator

Calculate your Body Mass Index using metric or imperial measurements. See your BMI category and healthy weight range.

Last updated: April 2026 · Source: NHS — BMI Calculator

Height (cm)

Weight (kg)

Disclaimer

This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.

How It Works

Body Mass Index (BMI) is calculated by dividing your weight in kilograms by the square of your height in metres: BMI = weight (kg) ÷ height (m)². It is used by the NHS as a screening tool to indicate whether your weight is in a healthy range for your height.

The NHS classifies BMI as follows: under 18.5 is underweight, 18.5–24.9 is a healthy weight, 25–29.9 is overweight, and 30 or above is obese. These ranges apply to most adults but may be less accurate for very muscular people, pregnant women, older adults and certain ethnic groups.

This calculator supports both metric (kg/cm) and imperial (stones, pounds, feet, inches) inputs and converts automatically. It shows your BMI value, NHS category and a visual indicator of where you fall on the scale.

Example: 80 kg, 175 cm tall

Height in metres: 1.75 m
BMI = 80 ÷ (1.75 × 1.75) = 80 ÷ 3.0625 = 26.1
NHS category: Overweight (25–29.9)
Healthy weight range for 175 cm: 56.7–76.6 kg

Source: NHS — BMI Calculator

Frequently Asked Questions

What is a healthy BMI range?: According to the NHS, a healthy BMI is between 18.5 and 24.9. A BMI below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is classified as obese.
Is BMI accurate for everyone?: BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat, so very muscular people may have a high BMI despite being healthy. It may also be less accurate for older adults, pregnant women, and certain ethnic groups.