Ideal Weight Calculator — 4 Formulas

Calculate ideal body weight using Devine, Robinson, Miller and Hamwi formulas plus WHO BMI range. Compare 4 clinical methods. Free, instant.

Medically reviewed by Dr. Ivan IbáñezNº Col. 17/05487Mar 13, 2026

How to use this calculator?

CalcVita. (2026). Ideal Weight Calculator — 4 Formulas. CalcVita. Retrieved October 16, 2026, from https://calcvita.com/en/calculators/ideal-weight

What Is My Ideal Weight? Comparing 5 Scientific Formulas

Understand how Devine, Robinson, Miller, Hamwi, and WHO BMI formulas estimate ideal weight, where they come from, and why body composition matters more than any single number.

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How does this calculator work?

This calculator applies four widely-used clinical formulas — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — each of which estimates ideal body weight from height and sex. It also displays the WHO healthy-weight range based on a BMI of 18.5 to 24.9. The average of the four formulas provides a single reference point, while the range lets you see the natural spread of estimates.

Why were these formulas created?

Most ideal body weight formulas come from clinical pharmacology, where they were used to dose drugs. Devine's equation, published in 1974 for gentamicin dosing, became the most widely used because the pharmacokinetics of several drugs correlate with it; Robinson and Miller later re-derived the coefficients by regression on height-weight tables and obtained very similar equations (Pai & Paloucek, 2000). Hamwi's formula predates the others and was designed for diabetes diet planning. Despite their origins, these formulas remain the most commonly referenced benchmarks for ideal weight.

What are the limitations?

None of these formulas account for body frame size, body composition, ethnicity, or age. An athlete with significant muscle mass may exceed formula estimates while being perfectly healthy. Conversely, a sedentary person within the "ideal" range could carry excess body fat. Use these numbers as a starting reference and consult a healthcare professional for personalized guidance.

Sources

Devine BJ. "Gentamicin therapy." Drug Intelligence & Clinical Pharmacy. 1974;8:650-5.
Robinson JD, et al. "Determination of ideal body weight for drug dosage calculations." Am J Hosp Pharm. 1983;40(6):1016-9.
Miller DR, et al. "Determining ideal body weight (and mass)." Am J Hosp Pharm. 1983;40(10):1622, 1625.
Hamwi GJ. "Therapy: changing dietary concepts." In: Danowski TS, ed. Diabetes Mellitus: Diagnosis and Treatment. New York: American Diabetes Association; 1964:73-8.
Pai MP, Paloucek FP. "The origin of the 'ideal' body weight equations." Ann Pharmacother. 2000;34(9):1066-9.
WHO Expert Committee. "Physical status: the use and interpretation of anthropometry." WHO Technical Report Series 854. 1995.

Frequently asked questions

How is ideal body weight calculated?: This calculator uses four widely used clinical formulas — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — which all estimate ideal weight based on height and sex. It also shows the WHO healthy BMI range (18.5-24.9) for your height.
Why do the four formulas give different results?: Each formula was published at a different time and for a different purpose: Devine for drug dosing (gentamicin), Robinson and Miller as regression refits of height-weight tables for dosing, and Hamwi for diabetes diet planning. Because the height-weight tables behind them broadly agree, the results differ by only a few kilograms. The average of the four gives a single reference point, and the WHO range reflects the natural variation in healthy body weight.
Does ideal weight account for muscle mass?: No. These formulas use only height and sex. Athletes with significant muscle mass may have an ideal body weight above formula estimates. Body composition analysis (DEXA, bioimpedance) gives a more complete picture.
Are these formulas accurate for very short or very tall people?: The formulas were developed for adults at least 152 cm (5 feet) tall. Below this height, the calculator shows base values and flags reduced accuracy. For very tall individuals, the WHO BMI range may be more reliable than the linear formulas.

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Frequently asked questions

How is ideal body weight calculated?

This calculator uses four widely used clinical formulas — Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) — which all estimate ideal weight based on height and sex. It also shows the WHO healthy BMI range (18.5-24.9) for your height.

Why do the four formulas give different results?

Each formula was published at a different time and for a different purpose: Devine for drug dosing (gentamicin), Robinson and Miller as regression refits of height-weight tables for dosing, and Hamwi for diabetes diet planning. Because the height-weight tables behind them broadly agree, the results differ by only a few kilograms. The average of the four gives a single reference point, and the WHO range reflects the natural variation in healthy body weight.

Does ideal weight account for muscle mass?

No. These formulas use only height and sex. Athletes with significant muscle mass may have an ideal body weight above formula estimates. Body composition analysis (DEXA, bioimpedance) gives a more complete picture.

Are these formulas accurate for very short or very tall people?

The formulas were developed for adults at least 152 cm (5 feet) tall. Below this height, the calculator shows base values and flags reduced accuracy. For very tall individuals, the WHO BMI range may be more reliable than the linear formulas.