Which formula should I use?

There is no single 'correct' one — they were derived for different clinical contexts, mostly drug dosing. Devine is the most widely cited in pharmacology and is often the default. Showing all four makes the disagreement visible, which is the most honest reading.

Why do the four results differ?

Each formula uses a different base weight at 5 ft and a different increment per inch. Those small constant differences compound with height, so a tall person can see a spread of 5–10 kg between the highest and lowest estimate.

What happens below 5 feet?

All four formulas are defined as a base weight at exactly 5 ft plus a positive amount per inch above it. They have no validated meaning below 5 ft, so this tool clamps the 'inches over 5 ft' term at zero — a person under 5 ft simply gets the 5-ft base weight. Treat sub-5-ft figures as a floor, not a real estimate.

Does ideal weight account for muscle or frame size?

No. These equations use only height and sex. A muscular athlete and a sedentary person of the same height and sex get identical numbers, even though their healthy weights differ. For body composition, look at body-fat percentage instead.

How is this different from BMI?

BMI takes your actual weight and height and returns a category. Ideal weight goes the other way: it predicts a target weight from height and sex alone. They answer different questions; use them together.

Is ideal body weight a medical diagnosis?

No. It is a population-level estimate used as a starting reference, for example to calculate medication doses. It is not a diagnosis or a personal goal. Any weight decision should involve a qualified healthcare professional.

Ideal Weight Calculator

Four classic clinical formulas, side by side, in kg and lb.

Buğra SözeriHealth

Updated June 27, 2026 · Published June 27, 2026

Reviewed by Convertitive Health Desk

Medical disclaimer: This calculator is a screening reference, not a medical diagnosis. Consult a qualified healthcare professional before making decisions based on the result.

“Ideal body weight” (IBW) is a clinical shorthand, not a personal goal. The four formulas below — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — were each built for a specific purpose, mostly drug-dosing and life-insurance tables, by fitting a base weight at 5 ft (60 in) of height plus a fixed amount per inch above that. They depend only on height and sex, so they say nothing about your frame size, muscle mass, age, or body composition. The calculator shows all four at once precisely because they disagree: the spread between them is the honest answer. For a screening figure that does account for your weight, see the BMI calculator; for energy needs, see the BMR & TDEE calculator.

Height (cm)

Formula	kg	lb
Devine (1974)	70.5	155.3
Robinson (1983)	68.9	151.9
Miller (1983)	68.7	151.6
Hamwi (1964)	72.0	158.8

These four equations are population-level estimates derived for clinical and actuarial use, not personal weight targets. They ignore frame size, muscle mass, age, and body composition, and they disagree with each other by several kilograms. Treat the range as context, not a goal, and consult a clinician for an individual target.

How to use

Choose sex
Each formula uses a different base weight and per-inch increment for males and females, so this changes every row.
Enter your height in centimetres
The calculator converts to inches internally (1 in = 2.54 cm) and computes how many inches you stand above 5 ft.
Read the range, not a single number
The four results are shown together in kg and lb. Use the spread as a rough band of population-typical weights for your height — not as a target to hit.

How the four formulas are built

Every equation has the same shape: a base weight for a 5-ft person plus an increment for each inch above 5 ft. They differ only in those two constants, which is why they fan out by several kilograms at taller heights.

Formula	Male (kg)	Female (kg)
Devine (1974)	50 + 2.3 × in	45.5 + 2.3 × in
Robinson (1983)	52 + 1.9 × in	49 + 1.7 × in
Miller (1983)	56.2 + 1.41 × in	53.1 + 1.36 × in
Hamwi (1964)	48 + 2.7 × in	45.5 + 2.2 × in

where in = max(0, height cm ÷ 2.54 − 60), the number of inches above 5 ft.

Frequently asked questions

Which formula should I use?: There is no single 'correct' one — they were derived for different clinical contexts, mostly drug dosing. Devine is the most widely cited in pharmacology and is often the default. Showing all four makes the disagreement visible, which is the most honest reading.
Why do the four results differ?: Each formula uses a different base weight at 5 ft and a different increment per inch. Those small constant differences compound with height, so a tall person can see a spread of 5–10 kg between the highest and lowest estimate.
What happens below 5 feet?: All four formulas are defined as a base weight at exactly 5 ft plus a positive amount per inch above it. They have no validated meaning below 5 ft, so this tool clamps the 'inches over 5 ft' term at zero — a person under 5 ft simply gets the 5-ft base weight. Treat sub-5-ft figures as a floor, not a real estimate.
Does ideal weight account for muscle or frame size?: No. These equations use only height and sex. A muscular athlete and a sedentary person of the same height and sex get identical numbers, even though their healthy weights differ. For body composition, look at body-fat percentage instead.
How is this different from BMI?: BMI takes your actual weight and height and returns a category. Ideal weight goes the other way: it predicts a target weight from height and sex alone. They answer different questions; use them together.
Is ideal body weight a medical diagnosis?: No. It is a population-level estimate used as a starting reference, for example to calculate medication doses. It is not a diagnosis or a personal goal. Any weight decision should involve a qualified healthcare professional.

About

Where these formulas came from

Hamwi (1964) was a rule-of-thumb for diabetic diet planning. Devine (1974) refined it for calculating drug doses and became the de facto pharmacology standard. Robinson and Miller (both 1983) re-fit the constants against Metropolitan Life insurance height-weight tables. None were intended as personal weight goals — they are reference equations.

When to ignore the calculator

Ideal-weight equations break down for athletes with high muscle mass, the elderly, amputees, people with significant edema, and anyone far from average build. In clinical settings, adjusted or lean body weight is often used instead. For an individual target, work with a clinician or dietitian rather than an online formula.

Sources & references

Authoritative references behind the math, constants, and tables on this page. Verified by Buğra Sözeri on the dates shown and re-checked at every deploy.

Devine BJ — Gentamicin therapy (Drug Intell Clin Pharm, 1974) — Origin of the Devine ideal-body-weight formula, derived for drug dosing and still the pharmacology default(as of 2026-06-27)
Pai MP, Paloucek FP — The Origin of the 'Ideal' Body Weight Equations (Ann Pharmacother, 2000) — Reviews the Devine, Robinson, Miller, and Hamwi equations and their constants; primary secondary reference for all four formulas on this page(as of 2026-06-27)
Robinson JD et al. — Determination of ideal body weight for drug dosage calculations (Am J Hosp Pharm, 1983) — Source of the Robinson formula constants, re-fit against Metropolitan Life tables(as of 2026-06-27)
Miller DR et al. — Ideal body weight calculation (Drug Intell Clin Pharm, 1983) — Source of the Miller formula constants. Hamwi's 1964 rule (Diabetes Mellitus: Diagnosis and Treatment) is the fourth equation. All four are population-level estimates, not personal targets.(as of 2026-06-27)