Ideal Weight Calculator

Estimate a healthy weight range using four established clinical formulas.

Please note: For general information only. This is not medical advice — speak to a doctor or registered dietitian before changing your diet, training or medication.

What the Ideal Weight Calculator does

Several formulas estimate ideal body weight from height alone. They were designed for medication dosing rather than body composition, so treat the healthy BMI range as the more meaningful target and the formulas as reference points.

Formula

Devine (men): 50 kg + 2.3 kg per inch over 5 ft
Devine (women): 45.5 kg + 2.3 kg per inch over 5 ft
Healthy BMI range: 18.5 × height² to 24.9 × height²

Inputs explained

Input	Unit	Required	Notes
Sex	one of 2 options	Yes	—
Units	one of 2 options	Yes	—
Height	cm or ft + in	Yes	Accepts 100 or more, up to 250.

How to use it

Choose Sex and Units.
Enter Height.
Select Calculate.

Worked example

A woman 165 cm tall.

Sex: Female
Height: 165 cm

Healthy BMI range 50.4–67.8 kg; Devine formula gives 57.0 kg.

Frequently asked questions

Why do the formulas disagree?

They were derived from different populations for different clinical purposes. The spread between them is a useful reminder that no single number is "correct".

Does frame size matter?

Yes. People with larger skeletal frames sit healthily above these estimates. Wrist circumference is a rough frame indicator.

Method and sources

Method. Four published height-based formulas — Devine, Robinson, Miller and Hamwi — computed side by side so the disagreement between them is visible rather than hidden behind one number.

Assumptions

The reader is an adult. None of these formulas is validated for children.
Height is the only body dimension used; frame size and body composition are not inputs.

Limitations

None of these formulas was derived as a health target. Devine was published to size drug doses, and the others follow the same lineage — they describe a population average, not a weight anybody should aim for.
They take no account of muscle mass, so an athlete reads as overweight, and none is adjusted for ancestry despite body proportions differing between populations.
The four disagree by several kilograms at the same height, which is the most useful thing the page shows: there is no single ideal weight to calculate.

Sources

Clinical Pharmacy: Case Studies — Case Number 25: Gentamicin Therapy — Drug Intelligence and Clinical Pharmacy 8(11):650–655 (McCarron and Devine), 1974. The Devine formula, and the fact that its original purpose was drug dosing rather than health assessment.