Ideal Weight Calculator

How this ideal weight calculator works

Enter your sex, height, and body frame size to get an estimated healthy weight range, calculated using four widely referenced medical formulas: Devine, Robinson, Miller, and Hamwi. All four were originally developed for clinical drug-dosing calculations and have since become common general reference points for ideal body weight.

The formulas

Devine (men): 50 kg + 2.3 kg per inch of height over 5 feet
Devine (women): 45.5 kg + 2.3 kg per inch of height over 5 feet
Robinson (men): 52 kg + 1.9 kg per inch of height over 5 feet
Robinson (women): 49 kg + 1.7 kg per inch of height over 5 feet
Miller (men): 56.2 kg + 1.41 kg per inch of height over 5 feet
Miller (women): 53.1 kg + 1.36 kg per inch of height over 5 feet
Hamwi (men): 48.0 kg + 2.7 kg per inch of height over 5 feet
Hamwi (women): 45.5 kg + 2.2 kg per inch of height over 5 feet

The frame size adjustment

Each formula result is adjusted by your selected frame size: small frame subtracts about 10%, large frame adds about 10%, medium frame applies no adjustment. Frame size is commonly estimated from wrist circumference relative to height.

Step-by-step

Convert your height to inches, then subtract 60 (5 feet) to find inches over the 5-foot baseline.
Multiply that figure by the per-inch rate for your sex and chosen formula.
Add the base weight for your sex to get that formula’s estimated ideal weight.
Apply your frame-size adjustment (±10%, or none for medium).
Compare all four formulas together to see your realistic range rather than a single number.

Worked example

A man who is 170 cm tall (about 66.9 inches, 6.9 inches over 5 feet) with a medium frame:

Devine: 50 + (2.3 × 6.9) = ≈ 65.9 kg
Robinson: 52 + (1.9 × 6.9) = ≈ 65.1 kg
Miller: 56.2 + (1.41 × 6.9) = ≈ 65.9 kg
Hamwi: 48.0 + (2.7 × 6.9) = ≈ 66.6 kg

This gives an estimated ideal weight range of roughly 65-67 kg for this height at a medium frame. With a large frame, each figure would shift about 10% higher; with a small frame, about 10% lower.

Common mistakes

Treating the result as a strict target. These formulas produce a population-level reference point, not a personalized medical prescription.
Ignoring body frame and muscle mass. A muscular or large-framed person may healthily weigh more than the unadjusted formulas suggest.
Using formulas designed for clinical dosing as fitness goals without accounting for individual differences in build.
Picking one formula and ignoring the others. The four formulas were built from different reference populations, so comparing all four gives a more honest range than trusting a single number.

Tips

Use this range as a general reference point alongside BMI and body fat percentage, not as a standalone target.
Estimate your frame size from wrist circumference relative to height rather than guessing.
Discuss any specific weight goal with a healthcare provider rather than relying on a single formula.

Which formula is more accurate, Devine, Robinson, Miller, or Hamwi?

None is definitively “more accurate”, they were developed at different times using different reference populations. Comparing all four gives a reasonable range rather than a single potentially misleading number.

How do I know my body frame size?

Frame size is commonly estimated from wrist circumference relative to height. A smaller wrist relative to height generally indicates a small frame, while a larger one indicates a large frame; medium frame covers most people.

Should I aim for the exact number this calculator gives me?

Not necessarily. Treat it as a general reference range. Individual factors like muscle mass, bone density, and body frame size all affect what’s actually healthy for you specifically.

How is this different from a healthy BMI weight range?

BMI-based ranges come from a population-wide height-to-weight ratio, while Devine, Robinson, Miller, and Hamwi were built specifically as clinical reference formulas. They often produce similar but not identical ranges.