Which formulas does it use?

Devine, the commonly tabulated rounded Robinson version, Miller, and Hamwi. All use a 5 ft basis plus a coefficient for each inch above it; below 5 ft, this calculator marks the result as a linear extrapolation.

Why do men and women get different results?

The historical equations specify different base weights and per-inch coefficients for male and female inputs. The calculator applies those published formula structures without making an individual assessment.

Is ideal weight the same as a healthy weight?

No. The four formula values are historical estimates, and the BMI 18.5–24.9 band is shown only as a separate reference. Neither is a personal diagnosis or target.

Does it work for very tall or short people?

The formulas extend linearly with height. For heights below their 5 ft (152.4 cm) basis, the calculator explicitly labels the values as linear extrapolations; unusual heights need extra caution.

Can I use it for children?

No. These are adult formulas. Children and teenagers need age- and growth-based references from a clinician.

Can I share a calculation?

Yes. Use Share to copy a link that reopens the calculator with the same height and sex.

Historical ideal-weight formula calculator

Enter your height in centimetres and pick your sex. The calculator shows Devine, the rounded Robinson version, Miller, and Hamwi separately, highlights their full range, and adds a separate BMI reference range.

Written by Kenneth Schrøder, Founder of WiseCalcs

Updated August 23, 2026·Sources verified August 23, 2026

Use it to compare how four historical height-based formulas differ, not to set a recommended target weight.

Historical formula range

71.5–77.3 kg

Devine formula: 75 kg
Robinson formula (rounded version): 72.6 kg
Miller formula: 71.5 kg
Hamwi formula: 77.3 kg
BMI reference range (18.5–24.9): 59.9–80.7 kg

For the entered height, the highlighted min–max span shows how much the four historical formulas disagree; it is not a recommended target weight. The BMI reference range is shown separately.

How does it work?

The four historical results are shown separately; no clinical significance is assigned to their arithmetic mean. Robinson uses the commonly tabulated rounded coefficients. Below 152.4 cm, the formulas are linearly extrapolated below their 5 ft basis. The separate BMI 18.5–24.9 range is a reference, not a personal target.

Historical ideal-body-weight formulas

\text{IBW} = \text{base} + k \times (\text{height}_{in} - 60)

IBW: Ideal body weight in kilograms.
base: Starting weight for 5 ft, set by formula and sex.
k: Kilograms added per inch above 5 ft.
height: Height in inches (centimetres ÷ 2.54).

For a 180 cm man, Devine gives 75.0 kg, the rounded Robinson version 72.6 kg, Miller 71.5 kg, and Hamwi 77.3 kg. The historical formula range is 71.5–77.3 kg.

Expert tips

These historical formulas use height and sex only. They do not assess body composition, age, health status, or an appropriate personal goal.

Method & sources

Height is entered in centimetres and converted to inches for the classic formulas. The headline is the minimum-to-maximum span across Devine, the rounded Robinson version, Miller, and Hamwi; no average is presented as a separate formula. The separate BMI reference range uses the 18.5–24.9 band.

Sources

Where this method comes from — use these references to understand the formula, assumptions, and limits.

Clinical Pharmacy: Case Studies — Case Number 25 Gentamicin Therapy — McCarron MM and Devine BJ, Drug Intelligence & Clinical Pharmacy (1974), verified 2026-08-23
Determination of ideal body weight for drug dosage calculations — Robinson et al., American Journal of Hospital Pharmacy (1983), verified 2026-08-23
Determining ideal body weight (and mass) — Miller et al., American Journal of Hospital Pharmacy (1983), PMID 6638023, verified 2026-08-23
Ideal body weight — a commentary — Chichester et al. (2021), reproducing the Hamwi MT (1964) bibliographic reference: Therapy: changing dietary concepts, in Diabetes Mellitus: Diagnosis and Treatment, vol. 1, pp. 73–78, verified 2026-08-23
Universal equation for estimating ideal body weight and body weight at any BMI — Peterson et al., American Journal of Clinical Nutrition (2016), verified 2026-08-23

How we calculate

Height is entered in centimetres and converted to inches for the classic formulas.
The headline is the minimum-to-maximum span across Devine, the rounded Robinson version, Miller, and Hamwi; no average is presented as a separate formula.
The separate BMI reference range uses the 18.5–24.9 band.
Below 152.4 cm, the historical formulas are linearly extrapolated below their 5 ft basis.

Limitations

These historical formulas use height and sex only. They do not assess body composition, age, health status, or an appropriate personal goal.

Rounding

Weights are shown to one decimal. The calculation uses full precision.

What this calculator does

This calculator compares four historical height-based formulas — Devine, the rounded Robinson version, Miller, and Hamwi. It shows every result and the full minimum-to-maximum span without assigning special status to an arithmetic average. The BMI reference range is a separate calculation.

How to use it

Enter your height in centimetres.
Pick the sex used by the historical formula coefficients.
Read the Devine, rounded Robinson, Miller, and Hamwi results.
Compare their highlighted min–max span with the separate BMI reference range.

A worked example

For a 180 cm man, Devine gives 75.0 kg, the rounded Robinson version 72.6 kg, Miller 71.5 kg, and Hamwi 77.3 kg. The historical formula range is therefore 71.5–77.3 kg; the separate BMI 18.5–24.9 reference range is about 59.9–80.7 kg.

How to interpret the range

These formulas were developed in older clinical and dietary contexts. They use height and sex only and do not assess body composition, age, health status, or an appropriate personal goal. The formula span shows disagreement between methods; the BMI band is a separate reference, not confirmation of the estimates.

Common mistakes

Entering height in metres or inches instead of centimetres.
Reading the formula span or BMI reference range as a personal recommendation.
Missing the extrapolation notice when height is below the formulas' 5 ft (152.4 cm) basis.
Applying these adult formulas to children or teenagers.

What this comparison can show

The comparison makes the assumptions and disagreement of four commonly cited historical formulas visible. It does not evaluate health or replace an individual assessment by a qualified professional.

FAQ

Which formulas does it use?: Devine, the commonly tabulated rounded Robinson version, Miller, and Hamwi. All use a 5 ft basis plus a coefficient for each inch above it; below 5 ft, this calculator marks the result as a linear extrapolation.
Why do men and women get different results?: The historical equations specify different base weights and per-inch coefficients for male and female inputs. The calculator applies those published formula structures without making an individual assessment.
Is ideal weight the same as a healthy weight?: No. The four formula values are historical estimates, and the BMI 18.5–24.9 band is shown only as a separate reference. Neither is a personal diagnosis or target.
Does it work for very tall or short people?: The formulas extend linearly with height. For heights below their 5 ft (152.4 cm) basis, the calculator explicitly labels the values as linear extrapolations; unusual heights need extra caution.
Can I use it for children?: No. These are adult formulas. Children and teenagers need age- and growth-based references from a clinician.
Can I share a calculation?: Yes. Use Share to copy a link that reopens the calculator with the same height and sex.

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