Ideal Weight Calculator
Ideal body weight (IBW) formulas estimate a reasonable target weight from your height and sex alone, using a fixed base value plus an increment for every inch above five feet. This calculator runs the four classic clinical formulas — Devine, Robinson, Miller, and Hamwi — which were originally developed for medication dosing rather than aesthetics, so they give a clinical reference point rather than a personal goal. Because none of them account for frame size or muscle, the result is best read alongside the BMI-based healthy weight range shown below.
Formula
IBW (kg) = base + perInch × max(0, heightInches − 60)
- base
- Sex-specific starting weight in kg (Devine male 50, female 45.5)
- perInch
- Weight added per inch over 5 ft (Devine 2.3 kg; Robinson male 1.9, female 1.7)
- heightInches
- Total standing height in inches
How it works
- Pick your sex and enter your height (feet and inches), then choose which formula to apply: Devine, Robinson, Miller, or Hamwi.
- Height is converted to total inches and the part above 60 inches (5 feet) is multiplied by the formula’s per-inch increment, then added to its sex-specific base weight in kilograms.
- The result is converted back to pounds and shown next to a BMI 18.5–24.9 healthy weight range for your height, so you can compare the single ideal figure against a realistic band.
Worked examples
A man who is 5 ft 10 in (70 inches) tall finds his ideal weight with the Devine formula.
- Inches over 60: 70 − 60 = 10.
- Devine male: 50 + 2.3 × 10 = 73 kg.
- Convert to pounds: 73 × 2.20462 = 160.9 lb.
Devine ideal weight ≈ 161 lb, within a healthy range of roughly 129–174 lb for that height.
The same 70-inch man compares the Robinson formula.
- Inches over 60: 70 − 60 = 10.
- Robinson male: 52 + 1.9 × 10 = 71 kg.
- Convert to pounds: 71 × 2.20462 = 156.5 lb.
Robinson ideal weight ≈ 157 lb — slightly lower than Devine, showing how formula choice shifts the target.
Frequently asked questions
- Which ideal weight formula should I use?
- No single formula is definitive. Devine is the most widely cited and is common in medicine; Robinson and Miller tend to read a little lighter, and Hamwi a little heavier. Comparing several gives a sensible range rather than one exact number.
- Why do these formulas only use height and sex?
- The classic IBW equations were designed as simple, reproducible references for drug dosing, so they deliberately ignore age, frame size, and body composition. That simplicity is also their main limitation for individual goal-setting.
- Is ideal weight the same as a healthy weight?
- Not exactly. A single ideal weight is one point inside the broad BMI 18.5–24.9 healthy band shown alongside it. Many people are perfectly healthy a little above or below their calculated ideal weight.
- Does ideal body weight work for very muscular people?
- Less well. Like BMI, these height-based formulas cannot tell muscle from fat, so athletes and heavily resistance-trained people often exceed their calculated ideal weight while still being lean.