Ideal Weight Calculator
Find your ideal body weight by height and gender using the Devine, Robinson, Miller and Hamwi formulas, plus the BMI-based healthy range.
About the Ideal Weight Calculator
How much should you weigh for your height? This ideal weight calculator answers with four classic medical formulas — Devine (1974), Robinson (1983), Miller (1983) and Hamwi (1964) — side by side in a simple table, in both kilograms and pounds. Pick your gender, enter your height in centimetres or feet and inches, and all four estimates appear instantly.
Each formula starts from a base weight at 5 feet and adds a fixed amount per additional inch. The Devine formula (50 kg + 2.3 kg per inch over 5 ft for men; 45.5 kg base for women) was originally created for calculating drug dosages and remains the most widely cited. Robinson and Miller are later refinements, while Hamwi is popular in clinical nutrition.
Because single-number targets are crude, the calculator also shows the healthy weight range for your height based on a BMI of 18.5–24.9 — the WHO's normal band. Most healthy weights fall inside this range, and frame size, muscle mass and body composition legitimately move your personal ideal within (or slightly beyond) it. Treat all figures as reference points, not prescriptions.
How to Use the Ideal Weight Calculator
- 1Select your gender — each formula uses different constants for men and women.
- 2Choose your height unit: centimetres or feet and inches.
- 3Enter your height.
- 4Compare the Devine, Robinson, Miller and Hamwi results with the BMI-based healthy range.
Frequently Asked Questions
How much should I weigh for my height?
There is no single correct number — the four formulas here typically span a range of several kilograms for the same height. A practical approach: aim to be inside the BMI 18.5–24.9 healthy range for your height, and use the formula results as a mid-range reference. Muscle mass, bone structure and age all shift the healthiest weight for an individual.
What is the Devine formula for ideal weight?
Devine (1974) gives ideal body weight as 50 kg + 2.3 kg per inch over 5 feet for men, and 45.5 kg + 2.3 kg per inch for women. It was developed for dosing medications whose distribution relates to lean mass, and it remains the standard 'IBW' used in pharmacy and critical care today, despite being a rough population estimate.
Why do the four formulas give different answers?
Each author derived their constants from different populations and purposes decades apart — Hamwi (1964) for quick clinical estimates, Devine (1974) for drug dosing, Robinson and Miller (1983) as statistical refinements. Differences of 2–6 kg between them are normal, especially at heights far from average. The spread itself is useful: it shows ideal weight is a range, not a point.
Do these formulas work for very short or very tall people?
They are least reliable at the extremes. All four assume a linear kilograms-per-inch relationship above 5 feet, which underestimates for very tall people and behaves poorly below 5 feet (some formulas subtract instead). For heights under about 152 cm, the BMI-based healthy range shown by this calculator is the more meaningful guide.
Is ideal weight different for athletes?
Often, yes. The formulas approximate lean-oriented population averages and do not account for high muscle mass, so strength athletes can healthily exceed every formula's number and even the BMI range. For athletic bodies, body fat percentage is a far better target metric — pair this tool with our body fat calculator for a fuller picture.