Ideal Weight Calculator

United Kingdom rules and figures

• The UK page shows weights in stones and pounds by default, so a result reads as 10 st 4 lb rather than 144.2 lb or 65.3 kg.
• The healthy range comes from NICE and NHS adult bands: 18.5 up to 24.9, with Overweight from 25 and Obesity class 1 from 30.
• NICE advises lower BMI thresholds, with overweight from 23, for several South Asian, Chinese, other Asian, Middle Eastern and Black backgrounds, and the ranges on this page do not apply them.
• The NHS BMI calculator for children covers ages 2 to 17, so the adult ranges here do not suit them.

Sources: NICE NG246: Classifying overweight and obesity in adults (checked 2026-11-08); NHS: Obesity diagnosis (checked 2026-11-08); NHS: BMI calculator (checked 2026-11-08)

How the ideal weight calculator works

Each formula is worked out in kilograms from your height, rounded to 0.1 kg, then converted to stones and pounds for display.

Devine (men) = 50 + 2.3 × (inches − 60) kg. Lorentz = H − 100 − (H − 150) ÷ 4 for men and ÷ 2 for women, with H in centimetres

• Height opens in centimetres at 170 and weight displays in stones and pounds. Picking feet and inches or kilograms is remembered.
• The page starts as a 30-year-old man with Moderate activity and Mesomorph build. Only gender changes the results, because activity and body type no longer scale the formulas.
• The BMI-Based Weight Ranges use the NICE and NHS bands, so the healthy range is 18.5 × height² to 24.9 × height², and the Underweight and Overweight ranges sit beside it.
• The lower NICE thresholds for some ethnic backgrounds are not applied here. The BMI Calculator has the checkbox for that.

How to use the ideal weight calculator

1. Enter your height. Use centimetres, or pick feet and inches. Heights from 100 to 250 cm give a result.
2. Add current weight if you like. Enter stones and pounds in the optional weight box. The page then says whether you are inside the healthy BMI band.
3. Pick gender on the Profile tab. Gender switches between the men's and women's versions of each formula. Age is stored, but it changes only one tip.
4. Read the six results. Individual Formula Results lists Robinson, Miller, Devine, Hamwi, Broca and Lorentz, so the spread is visible.
5. Keep or share the figures. Save Entry logs a dated weight, Copy puts the results on the clipboard and Export downloads a file.

Example: 170 cm man and 163 cm woman in stones

For a man of 170 cm the six formulas give Robinson 10 st 3.7 lb, Miller 10 st 5.5 lb, Devine 10 st 5.3 lb, Hamwi 10 st 7 lb, Broca 9 st 12.9 lb and Lorentz 10 st 3.3 lb, averaging 10 st 4 lb. His healthy BMI band is 8 st 5.9 lb to 11 st 4.6 lb. For a woman of 163 cm the average is 8 st 11 lb, against a healthy band of 7 st 10.4 lb to 10 st 5.9 lb.

When something else is a better fit

• When you want a BMI figure and NICE category rather than a weight, use the BMI Calculator.
• When you want to see composition rather than a single weight, use the Body Fat Calculator.
• When you need a goal linked to a health condition, use a GP or registered dietitian, who work from your history and test results.

Questions about the ideal weight calculator