Ideal Weight Calculator
Calculate ideal body weight target based on height, gender, and frame size.
An ideal weight calculator - or optimal weight calculator, ideal body weight calculator - estimates a target healthy body weight based on your height and sex, using one or more established medical formulas. This calculator uses the Devine formula, originally developed in 1974 for medical dosage calculations and now one of the most widely referenced ideal body weight formulas in clinical settings, alongside the Robinson, Miller, and Hamwi formulas which each produce slightly different estimates from the same inputs.
Enter your height and sex to see an estimated ideal weight and a healthy target range - useful as a general reference point rather than a precise individual target.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| Male 5ft 10in (70 inches) | 73.0 kg (161 lbs) | Healthy ideal target weight range is 145 - 165 lbs. |
Why Different Formulas Give Different Answers
The Devine, Robinson, Miller, and Hamwi formulas were each developed independently, using different reference populations and assumptions, which is why they can produce ideal weight estimates that differ by several pounds for the exact same height and sex. None is definitively 'more correct' than the others - they're all statistical approximations based on population averages, not measurements of any individual's actual healthy weight, which depends heavily on frame size, muscle mass, and body composition.
Ideal Weight vs. BMI: Two Different Approaches
BMI classifies a weight range as healthy based purely on height, without a sex-specific adjustment. Ideal body weight formulas like Devine build in a sex-based starting point (a base weight for 5 feet of height, plus a fixed amount per additional inch) that differs between men and women, since men and women have different average body compositions. In practice, the two approaches often point to similar healthy ranges, but ideal weight formulas were originally designed for medical dosing purposes, not as public health screening tools.
Frame Size and Individual Variation
None of the standard formulas account for frame size - whether someone has a naturally small, medium, or large bone and muscle structure - which can shift a genuinely healthy weight several pounds in either direction from the formula's estimate. A person with a large frame and significant muscle mass may have a healthy weight above the formula's estimate, while someone with a small frame may be healthy below it. These formulas work best as a starting reference, not a fixed target.
How to Use the Ideal Weight Calculator
- Open the Ideal Weight Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the ideal weight calculator works.
Frequently Asked Questions
Which ideal weight formula is most accurate?
The Devine formula is the most widely used benchmark in clinical and medical dosage settings, but no single formula is definitively more accurate for every individual - Robinson, Miller, and Hamwi formulas can each produce slightly different estimates for the same height and sex.
Why do ideal weight and BMI give different results?
Ideal weight formulas use a sex-specific starting point and a fixed amount per inch of height, while BMI uses a height-squared relationship without a sex adjustment. Both are general screening approaches, and it's normal for them to suggest slightly different weight ranges.
Does ideal weight account for muscle mass?
No. Ideal weight formulas are based only on height and sex, so muscular individuals may have a healthy weight above the formula's estimate, since these formulas can't distinguish muscle from fat.
What is the Devine formula based on?
The Devine formula was originally developed in 1974 to help estimate appropriate medication dosages based on body weight, and has since become a widely referenced general ideal body weight benchmark, though it wasn't originally designed as a public health target.
Is there a different ideal weight formula for children?
Yes. These adult formulas assume full-grown height and are not appropriate for children - pediatric growth is typically assessed using age- and sex-specific growth percentile charts instead.
Should I try to reach my exact 'ideal weight' number?
Not necessarily. These formulas provide a general reference range, not a precise individual target - frame size, muscle mass, and overall health matter more than hitting an exact number from any single formula.
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Last updated: September 29, 2026.