The Devine reference equation
The Devine equation begins at 50 kg for a male or 45.5 kg for a female at five feet, then adds 2.3 kg for every inch above that height. A 175 cm male is about 68.9 inches tall, so the estimate is about 70.5 kg. It is a reference formula, not a target prescribed for an individual.
Why height is insufficient
The formula has no input for frame size, muscle mass, age, pregnancy, disability, body composition, or health history. People of the same height can have quite different healthy and functional weights. Treating its output as a pass-or-fail threshold gives the equation more authority than it has.
Purpose of the formula
Devine was developed for estimating medication-related body size in clinical settings. That origin explains its reliance on height and sex constants. It is not designed to diagnose weight status, set a diet, or predict how a person will feel at the displayed number.
Small unit changes matter
Height is converted from centimetres to inches inside the relationship. A 5 cm change is nearly two inches, which moves the reference estimate by several kilograms. Use a measured height without shoes rather than a remembered rounded figure.
Beyond a reference weight
If weight, appetite, growth, pregnancy, medication, or exercise capacity is a concern, a clinician or registered dietitian can consider context that this height-only calculation cannot see. The useful output here is the reproducible formula result, not a judgement about a person.
Check the arithmetic in context
For a height near five feet, the equation changes only by the fixed kilograms-per-inch increment, so it cannot capture a gradual change in frame, strength, or function. It is better read as an old reference convention than as a destination. If it is being used to interpret a clinical document, confirm which equation and units that document actually specifies; several named reference formulas give different values from the same height.
A reference weight can be useful when a form explicitly asks for that historical formula, but it should not erase actual weight history or an individual's care plan. Height-based outputs are often rounded; retain the unrounded input height if another person needs to reproduce the calculation from the same formula.
It is informational only and is not medical or professional advice.