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Ideal Weight Calculator

This ideal weight calculator compares four published ideal body weight formulas — Devine, Robinson, Miller and Hamwi — for your height, next to the weight range that corresponds to a BMI of 18.5 to 24.9.

Formula sex category

Height cm

Historical adult height-based formulas, not personalized targets. They do not account for body composition or pregnancy. Supported height is at least 5 feet; do not extrapolate formulas below their baseline.

BMI 18.5 reference kg: 56.66
BMI 24.9 reference kg: 76.26

Formula	Estimate kg
Devine	70.46
Robinson	68.91
Miller	68.75
Hamwi	72.02

The four ideal weight formulas

Each formula starts with a weight at 5 feet (152.4 cm) and adds a fixed amount for every inch above that. The calculator converts your height from centimeters: inches over 5 ft = height cm ÷ 2.54 − 60.

Devine (1974)men 50 + 2.3 × in · women 45.5 + 2.3 × in
Robinson (1983)men 52 + 1.9 × in · women 49 + 1.7 × in
Miller (1983)men 56.2 + 1.41 × in · women 53.1 + 1.36 × in
Hamwi (1964)men 48 + 2.7 × in · women 45.5 + 2.2 × in
BMI reference weights18.5 × height m² and 24.9 × height m²

Results are in kilograms. "Formula sex category" picks the male or female constants; the formulas have no other inputs.

Worked example

Height 175 cm, which is 8.9 inches over 5 feet:

Formula	Male, kg	Female, kg
Devine	70.5	66.0
Robinson	68.9	64.1
Miller	68.8	65.2
Hamwi	72.0	65.1

For a man, Devine gives 50 + 2.3 × 8.9 = 70.5 kg. The four results span 68.8–72.0 kg for a man and 64.1–66.0 kg for a woman.

At the same height, a BMI of 18.5 to 24.9 is 56.7 to 76.3 kg — a range of about 20 kg, far wider than the formulas suggest.

Formula ranges by height

Height	Men, 4 formulas (kg)	Women, 4 formulas (kg)	BMI 18.5–24.9 (kg)
155 cm (5 ft 1 in)	50.8–57.6	47.8–54.5	44.5–59.8
165 cm (5 ft 5 in)	61.4–63.2	56.4–59.9	50.4–67.8
175 cm (5 ft 9 in)	68.8–72.0	64.1–66.0	56.7–76.3
185 cm (6 ft 1 in)	74.3–82.7	70.6–75.0	63.3–85.2
195 cm (6 ft 5 in)	79.8–93.3	75.9–84.1	70.3–94.7

The spread between formulas grows with height because they add different amounts per inch.

Where these formulas came from

Built for dosing, not goals

Hamwi published a quick rule of thumb in 1964. Devine's 1974 version was used to dose drugs such as gentamicin. Robinson and Miller fitted their 1983 equations to Metropolitan Life Insurance height-weight tables. None was designed as a weight-loss target.

Still used in hospitals

Clinicians still use Devine-style "predicted body weight" to set some drug doses and ventilator settings. Lung size, for example, depends on height and sex rather than current weight. In metric form it adds about 0.91 kg per cm above 152.4 cm.

A BMI-based alternative

Peterson and colleagues (2016) proposed one equation for any BMI: weight kg = 2.2 × BMI + 3.5 × BMI × (height m − 1.5). At BMI 22 and 175 cm it gives 67.7 kg. This calculator doesn't use it; it is shown for comparison.

These are estimates, not medical advice. A healthy weight depends on body composition, waist size, fitness, age and health conditions that no height formula captures. The formulas aren't meant for children or during pregnancy. Ask a doctor or registered dietitian before choosing a target.

Sources: Peterson CM, Thomas DM, Blackburn GL, Heymsfield SB. Universal equation for estimating ideal body weight and body weight at any BMI. Am J Clin Nutr 2016;103:1197–1203; Devine BJ, Drug Intell Clin Pharm 1974;8:650–5; Robinson JD et al., Am J Hosp Pharm 1983;40:1016–9; Miller DR et al., Am J Hosp Pharm 1983;40:1622; Hamwi GJ, in Diabetes Mellitus: Diagnosis and Treatment, American Diabetes Association, 1964; World Health Organization BMI classification. Checked 15 October 2026.

Frequently asked questions

What is the ideal weight for my height?+

There isn't one number. For a man 175 cm (5 ft 8.9 in) tall, the four formulas give 68.8 kg to 72.0 kg. For a woman 165 cm (5 ft 5 in) tall, they give 56.4 kg to 59.9 kg. A BMI of 18.5 to 24.9 corresponds to 50.4 kg to 67.8 kg at 165 cm. The formulas are reference points, not personal targets.

What is the Devine formula?+

Men: 50 kg + 2.3 kg for each inch over 5 feet. Women: 45.5 kg + 2.3 kg per inch over 5 feet. It was published in 1974 for drug dosing and is still the formula behind "predicted body weight" in many clinical settings. At 175 cm it gives 70.5 kg for a man.

What is the Hamwi formula?+

Men: 48 kg + 2.7 kg for each inch over 5 feet. Women: 45.5 kg + 2.2 kg per inch over 5 feet. Hamwi published it in 1964 in pounds (106 lb plus 6 lb per inch for men, 100 lb plus 5 lb per inch for women), and it was widely used by dietitians. At 165 cm it gives 56.4 kg for a woman.

What are the Robinson and Miller formulas?+

Both date from 1983 and add less per inch than Devine. Robinson: men 52 kg + 1.9 kg per inch over 5 feet, women 49 kg + 1.7 kg. Miller: men 56.2 kg + 1.41 kg per inch, women 53.1 kg + 1.36 kg. For a man 175 cm tall they give 68.9 kg and 68.8 kg.

How do I enter my height in feet and inches?+

The calculator takes centimeters. Multiply feet by 30.48 and inches by 2.54 and add them: 5 ft 8 in is 172.72 cm. Results are in kilograms; multiply by 2.2046 for pounds, so 70.5 kg is about 155 lb.

Which ideal weight formula is most accurate?+

None of them measures health. Robinson and Miller fitted their equations to the 1959 and 1983 Metropolitan Life Insurance height-weight tables. Hamwi and Devine published simple rules of thumb. A 2016 paper by Peterson and colleagues argued that a BMI-based equation is more consistent. The spread between the four results is a useful reminder of how rough they are.

Why do the formulas give different results?+

Each uses a different base weight at 5 feet and a different amount per extra inch. Hamwi adds the most per inch for men (2.7 kg) and Miller the least (1.41 kg), so the gap between them grows with height.

How does ideal weight compare with a healthy BMI?+

The calculator also shows the weights that match a BMI of 18.5 and 24.9 for your height — the World Health Organization's normal-weight range for adults. In the examples on this page, all four formula results fall inside that range.

Can I use it if I'm under 5 feet tall?+

No. Every formula starts at 5 feet (152.4 cm) and adds weight per inch above it. Going below that baseline means subtracting, which the formulas were never designed for, so the calculator stops at 152.4 cm.

Does it account for muscle, frame size or age?+

No. The formulas use only height and sex. They aren't for children or during pregnancy, and they can't tell muscle from fat. A muscular person can be well above every estimate and still be healthy. Talk to a doctor or dietitian before setting a weight goal.

Is my height or weight stored or sent anywhere?+

No. The estimates are calculated in your browser and nothing is uploaded or saved. Download summary saves a small text file to your own device.