Robinson Formula Ideal Weight Calculator

Robinson and colleagues re-fitted Devine's constants to a different dataset in 1983. Enter your height and sex for the estimate in kilograms and pounds.

The Robinson formula

Men: 52 kg + 1.9 kg for every inch of height over 5 ft. Women: 49 kg + 1.7 kg per inch over 5 ft. Below 5 ft the formula is not defined; this tool holds it at the base weight and you should read the healthy BMI range instead.

Worked example

A man 5 ft 10 in tall is 10 inches over 5 ft: 52 + 1.9 × 10 = 71 kg (157 lb). A woman the same height: 49 + 1.7 × 10 = 66 kg (146 lb).

How it compares

For that 5 ft 10 in man, Devine gives 73 kg, Hamwi 75 kg, Miller 70.3 kg and Robinson 71 kg — a spread of under 5 kg. Robinson sits near the bottom of that cluster because its per-inch slope (1.9 kg) is the second-gentlest. The gap between formulas widens the further you are from average height, so at 6 ft 4 in Hamwi and Miller can differ by 8 kg or more.

Ideal weight by height

Height	Devine	Robinson	Miller	Hamwi
5 ft 4 in, man	59 kg	60 kg	62 kg	59 kg
5 ft 10 in, man	73 kg	71 kg	70 kg	75 kg
6 ft 2 in, man	87 kg	83 kg	81 kg	91 kg
5 ft 4 in, woman	55 kg	56 kg	58 kg	54 kg
5 ft 8 in, woman	64 kg	63 kg	64 kg	63 kg

Figures rounded to the nearest kg. Your result above is exact for the height you entered.

The other ideal-weight formulas

Devine formula — the clinical default, and the parent calculator.
Miller — Also 1983, with the gentlest per-inch slope — the four formulas fan out most at the extremes of height.
Hamwi — The 1964 original, and the heaviest of the four — 48 kg (men) / 45.5 kg (women) plus 2.7 / 2.2 kg per inch.
Healthy BMI range — Not a single number — the whole weight band that lands in a BMI of 18.5–24.9 for your height.

Use it with the other checks

A height-only formula cannot see muscle or fat. Read this figure next to your BMI, your body-fat percentage, and — if you are setting calories — your TDEE. To move toward a target weight, run a modest deficit or surplus with the calorie calculator.

Source: Robinson JD et al., 1983. BMI cut-offs: WHO.

Related calculators

Related guides

Frequently asked questions

How is Robinson different from Devine?

Same structure — a base weight at 5 ft plus a fixed amount per inch — but Robinson lowered the base and the per-inch increment slightly after re-analysing a broader sample in 1983. In practice Robinson reads about 1 to 3 kg lighter than Devine across the normal height range.

Which formula do clinicians actually use?

Devine remains the default for drug dosing and ventilator settings because it is the one written into decades of protocols. Robinson, Miller and Hamwi are alternatives you will see in nutrition and research contexts. None is 'correct' — they are all rough height-only rules.

Does Robinson account for frame size or age?

No. Like Devine and Miller it uses height and sex only. Older frame-size adjustments (small / medium / large, judged from wrist or elbow breadth) added roughly ±10%; if you have a notably small or large frame, treat the number as the centre of a band that wide.

What if my height is between the table rows?

The calculator works in exact inches over 5 ft, so any height in the input gives an exact figure — the tables in the explainer are just landmarks.

Should I try to hit the Robinson number?

Use it as a reference, not a target. A healthy weight is a range several kilograms wide that depends on your muscle mass, body-fat percentage and health markers. Check it against your BMI and waist-to-height ratio rather than chasing one figure.

Last reviewed: September 2026. Figures and formulas are checked against their published sources; see the site's data notes.