Ideal Weight Calculator guide
Ideal Weight Calculator: Ideal Body Weight for Your Height
Use our ideal weight calculator to find your ideal body weight with the Robinson, Miller, Devine and Hamwi formulas, plus the healthy BMI range for your height.
By the AllCalculator editorial teamUpdated 16 October 20262 min read
What should I weigh? There's no single right answer, but formulas developed by doctors give a useful starting point. Our Ideal Weight Calculator shows the results of four of them, in kilograms and stones and pounds, alongside the NHS healthy weight range.
How to use the calculator (Ideal Weight Calculator)
- Choose your sex.
- Enter your height in centimetres or feet and inches.
You'll see the average of four formulas, each formula's result and the healthy BMI range for your height.
The formulas
Each formula starts with a base weight for someone 5 feet tall and adds a set amount for every inch over 5 feet.
| Formula | Men | Women |
|---|---|---|
| Robinson (1983) | 52kg + 1.9kg per inch | 49kg + 1.7kg per inch |
| Miller (1983) | 56.2kg + 1.41kg per inch | 53.1kg + 1.36kg per inch |
| Devine (1974) | 50kg + 2.3kg per inch | 45.5kg + 2.3kg per inch |
| Hamwi (1964) | 48kg + 2.7kg per inch | 45.5kg + 2.2kg per inch |
The Devine formula is still used in hospitals to work out doses of some medicines.
A worked example
With the calculator's default settings, a woman who is 168cm (about 5ft 6in) tall has an ideal weight of about 59.9kg (9st 6lb) on average across the four formulas. Her healthy BMI range is 52.2kg to 70.3kg.
Ideal weight versus healthy weight
The formulas give one number, but a healthy weight is really a range. The NHS uses BMI, which counts a BMI of 18.5 to 24.9 as healthy for most adults. Our Healthy Weight Calculator shows that range in more detail.
Frequently asked questions
Why don't the formulas agree?
They were based on different groups of people and were made for different purposes. Looking at the range of results is more useful than any one figure.
Do they allow for muscle?
No. They use only height and sex, so someone with a lot of muscle may be healthy well above their "ideal" weight. A Body Fat Calculator gives a better picture.
Do they work for short or tall people?
They're less reliable under 5 feet or over about 6ft 4in.
Sources and further reading
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.