Ideal weight calculator

How ideal weight is estimated

Unlike BMI, which gives a single number based on your current weight, ideal weight formulas estimate a target weight based on your height, sex, and — optionally — frame size. Four widely cited formulas are included here, each developed independently for clinical settings.

• Devine (1974) — the most commonly used formula in medicine and pharmacy, originally created to calculate drug dosages.
• Robinson (1983) — a revision of Devine that gives slightly lower estimates for men and slightly higher for women.
• Miller (1983) — produces the lowest estimates of the four; often considered more suitable for lighter frames.
• Hamwi (1964) — an older clinical rule of thumb, still in use, that tends to give slightly higher values than the others.

Because no single formula fits everyone, this calculator shows the result from all four alongside an average. Think of it as a range rather than a single target — the average gives a reasonable middle ground for most adults.

Frequently asked questions

Which ideal weight formula is the most accurate?

No single formula is universally accurate — each was developed for specific clinical purposes. The Devine formula (1974) is the most widely used in medicine and pharmacy. Comparing results from all four formulas gives a practical range rather than a single fixed number.

What is the difference between ideal weight and healthy weight?

Ideal weight is a calculated estimate based on height, sex, and frame size. Healthy weight is a broader range typically defined by a BMI between 18.5 and 24.9. The two concepts overlap but aren't identical — your ideal weight by formula may fall anywhere within the healthy BMI range.

How does frame size affect ideal weight?

Frame size (small, medium, large) reflects your bone structure and build. A larger frame naturally carries more bone mass, so the same height can support more weight while remaining healthy. This calculator adjusts the result by ±10% based on your selected frame size.

Do these formulas apply to children?

No. The Devine, Robinson, Miller, and Hamwi formulas were developed for adults. For children and adolescents, growth charts adjusted for age and sex are the standard tool.