Ideal Weight Calculator
Estimate your ideal body weight from height and sex (Devine formula).
How to use this tool
- Enter height and sex in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your ideal weight and the full breakdown beneath it.
Estimate your ideal body weight from height and sex (Devine formula).
⚠ This tool is for general information and education only and is not medical advice. Consult a qualified healthcare professional before making health decisions.
Formula
Ideal weight (male, kg) = 50 + 2.3 × (height in inches − 60)
Ideal weight (female, kg) = 45.5 + 2.3 × (height in inches − 60)
Where height in inches = height (cm) ÷ 2.54. This is the Devine formula (1974).
How it works
This calculator applies the Devine formula, originally developed to estimate ideal body weight for medication dosing in clinical settings, starting from a base weight at 5 feet (60 inches) and adding 2.3 kg per inch above that height.
The Devine formula was never intended as a fitness or aesthetic target; it is a rough clinical approximation with known limitations for very short, very tall, or highly muscular individuals. Individual ideal weight ranges vary with body composition and frame size.
Worked example
- Inputs: height 175 cm, male.
- Convert height to inches: 175 ÷ 2.54 = 68.898 inches.
- Inches above 60: 68.898 − 60 = 8.898.
- Apply Devine formula (male base 50 kg): 50 + 2.3 × 8.898 = 50 + 20.465 = 70.46 kg.
Ideal weight = 70.46 kg
Common mistakes to avoid
- Entering height in centimeters without converting to inches first — the Devine formula uses inches, and skipping the cm-to-inch conversion (divide by 2.54) produces a result in the wrong range entirely.
- Treating the Devine formula result as a fitness target rather than a reference — it was originally developed for medication dosing in 1974, not as a weight-loss goal.
- Applying the male formula to females or vice versa — the female baseline is 45.5 kg vs 50 kg for males, a difference that compounds with height.
Key terms
- Devine formula
- A 1974 clinical equation by B.J. Devine that estimates ideal body weight from height and sex, originally used for drug dosing calculations.
- Ideal body weight (IBW)
- A reference weight associated with optimal health outcomes for a given height; in practice, a healthy weight range is more useful than a single number.
- Base weight
- The starting weight in the Devine formula at exactly 5 feet (60 inches) tall: 50 kg for males and 45.5 kg for females.
- Frame size
- A qualitative descriptor (small, medium, large) of skeletal structure that affects what body weight is healthy for an individual's height.
- Height-weight proportionality
- The concept that healthy weight scales with height; linear formulas like Devine model this as a fixed kg-per-inch increment above a baseline.
Frequently asked questions
- Is ideal weight the same as a healthy BMI weight?
- Not exactly. The Devine formula predates BMI-based guidance and can diverge from BMI targets, particularly for very tall or very short individuals.
- Does muscle mass affect the ideal weight calculation?
- The Devine formula ignores body composition entirely — a muscular athlete and a sedentary person of the same height get the same result. It is a rough population-level reference.
- What is the formula for someone under 5 feet (60 inches) tall?
- The formula gives the base weight (50 kg for males, 45.5 kg for females) at exactly 60 inches. For heights below 60 inches the formula is not validated and may underestimate a healthy weight.