--- title: "Ideal Weight Calculator UK: Stones and Six Formulas | AumnI tools" description: "Enter height in centimetres or feet and inches to compare six ideal weight formulas in stones and pounds, beside the NICE and NHS healthy BMI band for your height." url: https://aumnitools.com/uk/tool/ideal-weight-calculator category: "Health" country: "United Kingdom" updated: 2026-11-08 --- # Ideal Weight Calculator Ideal weight formulas disagree by several pounds, so this page runs six of them for your height and shows the average in stones and pounds, the way weight is usually quoted in the UK. Beside them sits the weight range for the healthy BMI band, 18.5 to 24.9. They are rough guides, and a GP can judge what suits you. ## 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](https://www.nice.org.uk/guidance/ng246/chapter/identifying-and-assessing-overweight-obesity-and-central-adiposity) (checked 2026-11-08); [NHS: Obesity diagnosis](https://www.nhs.uk/conditions/obesity/diagnosis/) (checked 2026-11-08); [NHS: BMI calculator](https://www.nhs.uk/health-assessment-tools/calculate-your-body-mass-index/) (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. Formula: `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 to use the ideal weight calculator - **Seeing how much the formulas differ.** Compare Broca with Hamwi to see the gap between the lowest and highest results for your height. - **Finding a healthy band in stones.** Read the BMI-based range in stones and pounds for your height instead of converting from kilograms. - **Setting a talking point for a GP.** Note the healthy band and the average, and ask which target, if any, makes sense for you. ## What the ideal weight calculator does not do - The six formulas use height and gender only. They cannot allow for muscle, frame size or age. - Broca appears as the modified index, which is one of several variants in use. - The healthy band ignores ethnic background, so it may differ from NICE advice for some people. - An average of formulas is not a target. A GP or dietitian can tell you what weight suits your health. ## When something else is a better fit - **When you want a BMI figure and NICE category rather than a weight**, use the [BMI Calculator](https://aumnitools.com/tool/bmi-calculator.md). - **When you want to see composition rather than a single weight**, use the [Body Fat Calculator](https://aumnitools.com/tool/body-fat-calculator.md). - **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 ### Why do the six formulas give different answers? Each was built from different samples and rules. For a man of 170 cm the results run from 9 st 12.9 lb to 10 st 7 lb, so a spread of about 8 lb is normal. ### What does the healthy range mean? It is the weights that give a BMI from 18.5 to 24.9 at your height, per NICE and NHS bands. For 170 cm that is 8 st 5.9 lb to 11 st 4.6 lb. It is not a target. ### Can I enter my weight in pounds only? Yes. Change Weight Unit to lb and type the total, or to kg. The page stores the formulas in kilograms and shows whichever unit you pick. ### Why does activity level not change anything? The page now shows each formula as published, and activity and body type are kept only in the profile. Only gender and height change the six figures. ## Related tools - [BMI Calculator](https://aumnitools.com/tool/bmi-calculator.md): Works out BMI and its category from height and weight, with the healthy weight range - [Body Fat Calculator](https://aumnitools.com/tool/body-fat-calculator.md): Estimates body fat from neck, waist and height tape measurements with the US Navy formula - [Calorie Calculator](https://aumnitools.com/tool/calorie-calculator.md): Estimates BMR and daily calorie needs, with gram targets for protein, carbs and fat ## About this page Runs in your browser: what you enter is processed on this device and is not uploaded. Your profile, goals and weight history are kept in local storage on this device only, including entries you have deleted until you empty Recently deleted. General information only, not medical advice. Talk to a doctor or other health professional about decisions that affect your health. Last checked against the tool's code on 2026-11-08. Interactive version: https://aumnitools.com/uk/tool/ideal-weight-calculator