Ideal Weight Calculator: Find Your Healthy Weight Range

The calculator needs only two inputs: your height and your sex. Measure your height without shoes, ideally in the morning, and enter it in centimetres or switch to feet and inches.

Step by step

1. Choose your height unit. Centimetres or feet and inches — the calculator converts everything to inches internally.
2. Enter your height. Use your barefoot morning height; a couple of centimetres of slouch changes the answer by roughly a kilogram.
3. Select your sex. The formulas differ by sex because they were fitted to different reference populations.
4. Press Calculate. You get all four formula results in kg and lb, plus the range across them.

Read the range, not one number

No single formula is "correct" — they were developed between the 1960s and 1980s for different purposes, from drug dosing to insurance tables. Where they agree, you have a solid target zone; where they differ, the truth is somewhere in between. A result that sits inside the 4-formula range is a reasonable goal for most adults.

Devine is the original, created to estimate drug doses, and it is still the one most clinicians recognise. Robinson and Miller adjusted the base weights and slopes to better fit average builds, while Hamwi gives the highest values of the four and is often used as a generous upper bound.

Formula	Tends to give	Often used as
Devine	Middle of the range	The classic reference, still used in dosing
Robinson	Slightly below Devine	A leaner target for average builds
Miller	The lowest values	A conservative lower bound
Hamwi	The highest values	A generous upper bound

Ideal weight is not the same as a healthy BMI

These formulas output one weight per height, while BMI gives you a range (18.5 to 24.9) that accounts for different builds. The two usually agree: for most heights, the formula results land inside the healthy BMI band. If you want the band rather than a point estimate, check your BMI with our BMI calculator and compare — a weight that satisfies both is a well-supported target.

Start with the worked example numbers above: a 178 cm man gets 70.4 to 75.2 kg. If his actual weight is 73 kg, he is comfortably inside the range. If it is 90 kg, every formula agrees he is above the ideal zone — and that agreement across four independent formulas is stronger evidence than any single number.

When the formulas do not apply

These formulas were fitted to average adults and ignore frame size, muscle mass and age. A strength athlete can be "overweight" by every formula while carrying very little fat, and older adults often do better slightly above the formula range. Children, teenagers and pregnant women should not use these formulas at all — the NHS BMI calculator explains which measures suit which groups.

Using the range as a goal

Pick the middle of your 4-formula range as an initial goal, then adjust by how you look, feel and perform. If you lift weights, aim toward the top of the range; if you are slightly built, the bottom is fine. Re-check every few months — the target only changes if your height does, but your progress toward it is what matters.

Three common measures answer three different questions. Ideal weight asks "what should I weigh for my height", BMI asks "is my weight proportionate", and body fat percentage asks "how much of me is fat". None of them sees the full picture alone.

Measure	Inputs	Best for	Blind spot
Ideal weight formulas	Height, sex	A concrete target number	Ignores build and muscle
BMI	Height, weight	Quick screening bands	Cannot tell muscle from fat
Body fat %	Circumferences or calipers	True composition	Harder to measure well

Combine them for a fuller picture

Use the formulas on this page for your target, BMI for a quick sanity check, and body fat percentage when you want to know whether weight change is fat or muscle. Our body fat calculator uses the U.S. Navy circumference method, which needs only a tape measure and pairs naturally with the target you found here.