Ideal Weight Calculator
Enter your sex and height to get an estimated healthy weight range using the Devine and Robinson formulas.
Formula verified July 2026
Estimated ideal weight range
0 kg
Based on the Devine and Robinson formulas, two commonly used medical estimates.
How this ideal weight calculator works
Enter your sex and height to get an estimated healthy weight range, calculated using two widely referenced medical formulas: Devine and Robinson. Both were originally developed for drug-dosing calculations in clinical settings 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
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 formula.
- Add the base weight for your sex to get the estimated ideal weight.
- Repeat with the second formula to get a 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):
- Devine: 50 + (2.3 × 6.9) = 50 + 15.9 = ≈ 65.9 kg
- Robinson: 52 + (1.9 × 6.9) = 52 + 13.1 = ≈ 65.1 kg
This gives an estimated ideal weight range of roughly 65-66 kg for this height.
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 these formulas suggest.
- Using formulas designed for clinical dosing as fitness goals without accounting for individual differences in build.
Tips
- Use this range as a general reference point alongside BMI and body fat percentage, not as a standalone target.
- Body frame size (small, medium, large) can shift a healthy weight meaningfully above or below these formulas.
- Discuss any specific weight goal with a healthcare provider rather than relying on a single formula.
Which formula is more accurate, Devine or Robinson?
Neither is definitively “more accurate”, they were developed at different times using different reference populations. Showing both gives a reasonable range rather than a single potentially misleading number.
Why do these formulas only use height and sex?
They were originally designed for quick clinical estimates, such as medication dosing, where a simple, fast calculation was more valuable than one requiring frame size or body composition data.
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 and Robinson were built specifically as clinical reference formulas. They often produce similar but not identical ranges.