NHS Weight Calculator
This independent UK healthy-weight calculator estimates an adult weight range from height using current NHS/NICE BMI thresholds. It does not define one perfect or ideal body weight and is not an official NHS calculator.
Important: This is a BMI-based reference for adults aged 18 or over. Do not use it during pregnancy or as a diagnosis. BMI cannot distinguish muscle from fat.
What is the NHS weight calculator?
People often search for an NHS ideal weight calculator, but current NHS and NICE guidance does not prescribe one universal ideal weight. BMI is used as a practical screening measure, and waist-to-height ratio can add information about central body fat. This tool therefore gives a BMI-based healthy-weight reference rather than claiming there is one perfect weight.
How to use it
- Enter your height in centimetres.
- Select the relevant ethnic-background threshold group.
- The calculator shows the approximate body weights corresponding to the healthy BMI reference range.
Formula and current UK methodology
BMI is weight in kilograms divided by height in metres squared. Rearranging the formula gives weight = BMI × height². NICE classifies a BMI of 18.5 to 24.9 as healthy for most adults. For people from South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean backgrounds, cardiometabolic risk occurs at lower BMI, with overweight starting at 23; this calculator therefore uses 22.9 as the upper healthy reference for that option.
Worked example
For a height of 170 cm (1.70 m), the general adult BMI reference of 18.5 to 24.9 corresponds to approximately 53.5 kg to 72.0 kg. This is a screening range, not a personal target.
Use BMI alongside waist-to-height ratio
NICE recommends waist-to-height ratio alongside BMI in adults with BMI below 35 kg/m². NHS guidance says to try to keep your waist measurement to less than half your height. This can provide additional information because BMI does not show where body fat is carried.
Limitations
BMI is not a direct measure of body fat and should be interpreted cautiously in people with high muscle mass and in older adults. This adult calculator is not designed for children, pregnancy, eating disorders or conditions that affect height. Individual health cannot be determined from weight alone.
Authoritative sources
- NHS: BMI calculator for adults
- NICE NG246: identifying and assessing overweight, obesity and central adiposity
- NHS: waist-to-height ratio calculator
Related calculators
- NHS Calculator
- BMI Calculator NHS
- How Much Weight Have I Lost Calculator NHS
- Waist to Hip Ratio Calculator NHS
- BMI Calculator NHS Child
FAQs
What is my ideal weight according to the NHS?
The NHS does not set one ideal weight for every person. BMI and, where appropriate, waist-to-height ratio are used as practical measures to help assess weight-related health risk.
What BMI is a healthy weight for most adults?
NICE classifies BMI 18.5 to 24.9 kg/m² as healthy for most adults, while some ethnic groups have lower thresholds for overweight because health risks occur at lower BMI.
How is the weight range calculated?
The calculator rearranges the BMI formula: weight in kilograms equals BMI multiplied by height in metres squared.
Can children use this calculator?
No. Children and teenagers need age- and sex-adjusted BMI centiles rather than adult BMI thresholds.
Medical disclaimer: This independent calculator is for general information only. It is not an NHS diagnostic service or a personalised weight target.