Ideal Weight Calculator
Find the healthy weight range for your height, and see what the four classic ideal weight formulas say side by side. They disagree with each other, and the gap between them is the most useful part of the answer.
Fill in the fields to see your result.
Where these formulas came from
The ideal weight equations were never designed to tell you what to weigh. They were built so that doctors could calculate drug doses for patients whose actual weight would give the wrong answer — anaesthetic and chemotherapy dosing in particular, where fat tissue does not take up the drug the way lean tissue does.
Devine published his in 1974, and it stuck because it was simple and became the standard for dosing. Robinson and Miller both published revisions in 1983 after fitting the idea to real population data, and Hamwi's version from 1964 was designed to be worked out in your head at a bedside. None of them had any interest in what a person should look like.
The four formulas
All of them start from a base weight at five feet, then add a fixed amount per inch above that. The differences are entirely in those two constants.
Because they were fitted to different groups, they disagree — usually by five kilos or more across the set, and the gap widens the further you are from average height. Below five feet the formulas break down entirely, which is why very short heights are handled by the BMI range instead.
Why the range matters more than the number
The headline figure on this page is not one of the four formulas. It is the weight range that puts you inside a BMI of 18.5 to 25, which is the range health bodies actually use. It is deliberately wide, because the honest answer to "what should I weigh" spans several kilos for anyone.
Where you sit inside that range depends on things no equation knows: how much muscle you carry, your frame, your age, and what your weight has historically been. Someone at the top of the range who lifts weights and someone at the bottom who does not may be equally healthy.
What this cannot tell you
| Factor | Included? |
|---|---|
| Height | Yes |
| Sex | Yes |
| Muscle mass | No |
| Frame size | No |
| Age | No |
| Body fat distribution | No |
That list is why a number from this page should never become a target you chase. If you want a figure that actually reflects your body composition, measure your body fat percentage instead — it at least tries to tell fat from muscle.
Common questions
Is there really one ideal weight?
No, and that is the honest answer. The formulas here were built for clinical drug dosing, not for telling people what to weigh. They ignore your frame, your muscle and your age. A healthy range spanning several kilos is a far more truthful answer than any single figure.
Which ideal weight formula is the best one?
None of them is clearly superior. Devine is the most widely used because it became the standard for medication dosing. Robinson and Miller were later attempts to fit real population data more closely and tend to give slightly different numbers. Hamwi is the oldest and quickest to do in your head. Treat the spread between them as the useful information.
Why do the formulas disagree with each other?
Because they were fitted to different populations at different times, using different assumptions. The gap between the highest and lowest is usually several kilos. That spread is not an error — it is a reminder that no equation knows anything about your particular body.
Do these formulas account for muscle?
Not at all. They only know your height and sex. If you lift seriously, every one of these numbers will read low for you, in the same way BMI reads high. Body fat percentage is a far better guide in that case.
What about frame size?
Frame size is usually estimated from wrist circumference or elbow breadth, and it shifts the target by roughly ten percent either way. None of the four formulas here include it, which is one more reason to read the result as a range rather than a target.
Should I try to reach this number?
Not as a goal in itself. The healthy BMI range is a reasonable place to aim, but where you land inside it depends on your build and how you live. Rapid change to hit a specific figure tends to be worse for you than being a few kilos outside the range.
Related calculators
Please note: CalcuLane gives estimates for general information only and is not medical advice, a diagnosis or a treatment plan. These figures are population averages and cannot account for your individual circumstances. Always speak to a doctor or qualified health professional about your own health.