👤 Ideal Weight Calculator
Devine formula ideal body weight estimate. Runs privately in your browser.
Where the Devine formula came from
The Devine formula, dating from 1974, assigns 50 kg to a 1.52 m (5 ft) man and adds 2.3 kg per additional inch of height — 45.5 kg plus the same increment for women. It was originally derived to standardise drug dosing, not to set fitness goals, and it remains in clinical use precisely because it is simple and anchored to real dosing practice.
Because it is a single formula, it ignores frame size, muscle mass and age. The result is a midpoint, not a mandate: a broad-framed person may be perfectly healthy several kilograms above it, and the same weight means different things at different body compositions. Compare it with your BMI category and how you actually feel and function.
Devine, Robinson, and the alternatives
Devine (men): 50 kg + 2.3 kg per inch over 5 feet. Devine (women): 45.5 kg + 2.3 kg per inch over 5 feet. The calculator converts the result to pounds for imperial readers.
Worked through: a man at 1.80 m
A man at 1.80 m (about 70.9 inches): 9.9 inches over 5 ft × 2.3 = 22.8, so the estimate is 72.8 kg — roughly 160 lb. A woman of the same height gets 68.3 kg. A 1.60 m woman: 2.9 inches over 5 ft gives 45.5 + 6.7 = 52.2 kg.
Why 'ideal' deserves the scare quotes
- Treating one formula's output as a target range. Clinicians often use a ±10% band around any ideal-weight estimate.
- Ignoring frame size and body composition — the original reasons the formula came with wide error bars.
- Using it for adolescents. The formula applies to adults; growing bodies need paediatric charts.
- Confusing a healthy weight with a cosmetic goal — the two frequently differ.
Ideal weight questions
Why do different calculators give different ideal weights?
They use different formulas — Devine, Hamwi, Robinson, Miller. Differences of 3–5 kg at the same height are normal and reflect the era and purpose of each equation.
Is Devine the most accurate?
No formula is 'accurate' for individuals; Devine is the one most used in clinical dosing contexts. Treat any result as the centre of a range.
What if I am very muscular?
Lean mass raises healthy weight above the formula's estimate. Use BMI categories cautiously and favour composition measures.
Does age change the estimate?
The formula itself does not vary with age, though healthy body composition does shift across adulthood.
Should I try to reach exactly this number?
No. Health outcomes track ranges and habits, not a single kilogram value. Use the figure as a reference point, nothing more.
Other health tools
Tip: double-check inputs before relying on results for important decisions.