Devine Ideal Body Weight

What the Ideal Weight Calculator Does

This tool estimates your ideal body weight (IBW) from your height and sex using the Devine formula, returning a single target figure in kilograms. It gives a quick reference point rather than a personalized health prescription.

It is useful for anyone curious how their weight compares to a standard benchmark, and it is widely used in clinical settings. The Devine formula was originally created to help calculate medication doses that depend on body size, so it remains common among nurses, pharmacists, and physicians.

How the Devine Formula Works

The Devine formula (B. J. Devine, 1974) uses your height in inches and applies a fixed base weight plus an increment for every inch above 5 feet (60 inches). The two versions are:

Both formulas only add weight above 60 inches. If you are exactly 5 feet tall, the height term is zero, so a man's IBW is 50 kg and a woman's is 45.5 kg. The calculator handles the inch conversion automatically if you enter height in centimeters or feet and inches.

• Male: IBW (kg) = 50 + 2.3 x (height in inches - 60)
• Female: IBW (kg) = 45.5 + 2.3 x (height in inches - 60)

Worked Example

Take a man who is 5 feet 10 inches tall. That is 70 inches, so the height term is 70 - 60 = 10 inches above the baseline.

Plug it in: IBW = 50 + 2.3 x 10 = 50 + 23 = 73 kg (about 161 lb).

For a woman of the same height (70 inches): IBW = 45.5 + 2.3 x 10 = 45.5 + 23 = 68.5 kg (about 151 lb). The 4.5 kg gap between the two results is constant at every height, reflecting the different base values in the formula.

Common Mistakes and Limitations

The most frequent error is a unit mix-up. The formula expects height in inches; entering centimeters directly will give a meaningless number. Always confirm 1 inch = 2.54 cm, so 60 inches equals 152.4 cm.

Keep these limits in mind when reading your result:

• It is height- and sex-based only, so it ignores muscle mass, frame size, and body composition.
• It can read low for very tall people and short people, where the linear model is less reliable.
• It does not apply to children, pregnant women, or people with significant fluid retention or edema.
• Athletes with high muscle mass may exceed their IBW while being perfectly healthy.

How to Use the Result

Treat IBW as one data point, not a goal you must hit exactly. Devine produces a single number, whereas a healthy weight is realistically a range. Comparing it against your Body Mass Index (BMI) and waist measurement gives a fuller picture.

Other formulas, such as Robinson, Miller, and Hamwi, use slightly different constants and will yield results a few kilograms apart. None is definitively correct, so consistency matters more than the specific formula you pick. For weight goals tied to health conditions or medication, use this estimate as a starting point and confirm it with a doctor or dietitian.