Ideal Weight Calculator
Estimate your ideal body weight from your height and gender using four classic formulas — Devine, Robinson, Miller and Hamwi — alongside the healthy weight range based on BMI, in metric or imperial units.
Understanding the Ideal Weight Calculator
The Ideal Weight Calculator estimates a healthy body weight from your height and gender. It runs four classic clinical formulas side by side — Devine, Robinson, Miller and Hamwi — and adds the healthy weight range derived from BMI, so you can see both single-number estimates and a sensible target band. Choose metric (cm) or imperial (ft/in) units and switch gender to see how the constants change. Everything runs in your browser with no data sent anywhere. Because these methods rely on height alone, they are general references rather than personalised targets, and the results pair naturally with a BMI check of your current weight.
How it works
Each formula starts from a baseline weight at 5 feet (60 inches) and adds a fixed amount for every inch above that. The tool converts your height to total inches, computes "over" as the inches above 60 (never below zero), then applies each method's gender-specific constants. Devine, Robinson, Miller and Hamwi use different baselines and per-inch increments, which is why their numbers differ slightly. Separately, the healthy BMI range is found by multiplying BMI 18.5 and 24.9 by your height in metres squared. Results are calculated in kilograms and converted to pounds when imperial units are selected. People shorter than 5 feet receive the baseline weight.
Worked example
A woman who is 165 cm tall is about 64.96 inches, so "over" is 4.96 inches. Devine gives 45.5 + 2.3 × 4.96 ≈ 57.0 kg, Robinson 49 + 1.7 × 4.96 ≈ 57.4 kg, Miller 53.1 + 1.36 × 4.96 ≈ 59.8 kg, and Hamwi 45.5 + 2.2 × 4.96 ≈ 56.4 kg. Her height in metres is 1.65, so the healthy BMI range is 18.5 × 1.65² to 24.9 × 1.65², roughly 50.4 to 67.8 kg — a band that comfortably contains all four estimates.
Tips & common mistakes
- Treat the four formulas as a range of opinions, not one exact target — the healthy BMI band is the most widely accepted reference.
- Select your gender carefully: the constants differ, so the same height yields different ideal weights for men and women.
- These methods ignore muscle, frame size and age, so athletes and very muscular people often weigh more than the estimate while staying healthy.
- Pair this with the BMI calculator to compare your current weight against the healthy range.
- Switch between metric and imperial to double-check the figures in whichever unit feels natural.
- Use the result as a starting point for a conversation with a doctor or dietitian, not as a diet goal on its own.
Sources & methodology
- • Devine BJ (1974), gentamicin dosing — origin of the Devine ideal body weight formula
- • Robinson JD et al. (1983) and Miller DR et al. (1983), revised ideal body weight equations
- • Hamwi GJ (1964), rule-of-thumb method for estimating desirable body weight
- • World Health Organization BMI classification (healthy range 18.5–24.9)
Related tools
Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.
How to Use This Calculator
- 1Choose your gender and switch between Metric or Imperial units.
- 2Enter your height, then click Calculate Ideal Weight.
- 3Compare the formula estimates with the healthy range — then check your current number with the BMI calculator.
Frequently Asked Questions
Which ideal weight formula is best?
There is no single "best" one — Devine, Robinson, Miller and Hamwi are all estimates that give slightly different numbers. For everyday use, the healthy BMI weight range (a band rather than one figure) is the most widely accepted reference, while Devine is common in clinical drug dosing.
Does ideal weight differ by gender?
Yes. Every formula here uses different constants for men and women because, on average, women carry a higher proportion of body fat and have a lighter frame at the same height. That is why selecting your gender changes the results.
Is muscle mass accounted for?
No. These formulas use only your height (and gender), so they cannot tell the difference between muscle and fat. Very muscular or athletic people may sit above their "ideal" weight while being perfectly healthy. For a fuller picture, pair this with the BMI calculator and a body fat estimate to judge whether you are at a healthy weight for your fitness level.