Plot No. 43 · Health & Fitness
Ideal Weight Calculator
Work out a target body weight for your height using the Devine formula. It converts your height to inches, then for men adds 2.3 kg per inch over 5 feet to a 50 kg base (45.5 kg for women), and also shows the wider weight band that keeps your BMI between 18.5 and 24.9.
The Devine figure is a height-only reference and ignores frame size and muscle. It is an estimate, not medical advice.
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How ideal weight is worked out
This tool uses the Devine formula, a clinical rule of thumb from 1974. It converts your height to inches, starts from a base of 50 kg for men or 45.5 kg for women at 5 feet (60 inches) tall, and adds 2.3 kg for every inch above that. The result is a single reference weight rather than a strict goal.
Because one number can feel falsely precise, the calculator also shows a healthy weight band derived from BMI. It multiplies 18.5 and 24.9 by your height in metres squared to give the lower and upper ends of a normal-BMI weight, so you can see a realistic target window around the Devine figure.
How to use the ideal weight calculator
- Select your sex, since the Devine base weight differs by 4.5 kg between men and women.
- Enter your height in centimetres; the tool converts it to inches internally for the Devine formula.
- Compare the single Devine weight against the healthy BMI range and aim to sit somewhere inside that band rather than hit an exact figure.
Worked examples
Average-height man
Inputs: Male, height 178 cm (about 70.1 inches)
Result: Devine ideal weight of about 73.2 kg, inside a healthy BMI range of roughly 58.6 kg to 78.9 kg.
Average-height woman
Inputs: Female, height 165 cm
Result: Devine ideal weight of about 56.9 kg, with a healthy BMI range of roughly 50.4 kg to 67.8 kg.
Limitations and common mistakes
Edge cases and limitations
- The Devine formula was designed to dose medication, not to set fitness goals, so it ignores frame size, muscle and body composition.
- It can read low for tall, muscular people and for those with a large frame.
- Below about 5 feet of height the formula gives weights that are too low, since it was built around taller adults.
Common mistakes
- Treating the single Devine number as a precise target instead of a reference point inside the healthy range.
- Entering height in inches or feet; this calculator expects centimetres and converts for you.
Frequently asked questions
What is the Devine formula?
It is a clinical rule of thumb from 1974: 50 kg for men or 45.5 kg for women at 5 feet tall, plus 2.3 kg for every inch above that. A 178 cm man is about 70.1 inches, so 50 plus 2.3 times 10.1 gives roughly 73.2 kg.
Why show a range as well as a single number?
A single ideal weight feels precise but real bodies vary. The healthy BMI band, 18.5 to 24.9 times your height in metres squared, gives a realistic target window. For a 1.78 m person that band runs from about 58.6 kg to 78.9 kg.
Is the Devine weight a goal I should hit exactly?
No. The Devine formula was built to dose medication, not to set fitness goals, and it ignores frame size and muscle. Use it as a reference point inside the healthy BMI range rather than a number to chase.
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