Ideal Weight Calculator

An ideal body weight (IBW) calculator estimates a target weight for your height and sex using four well-known clinical formulas — Devine, Robinson, Miller and Hamwi — and shows the average of all four alongside a healthy weight range derived from BMI. It is a quick reference for anyone who wants a sensible weight goal: people starting a fitness journey, those tracking weight loss or gain, and anyone curious how their current weight compares to a clinical estimate. It is a screening and orientation tool, not a diagnosis, and it does not replace advice from a doctor or registered dietitian.

These formulas were originally created for medicine, not aesthetics. Many drug doses, anaesthesia volumes and ventilator settings are calculated per kilogram of ideal body weight rather than actual weight, which is why precise formulas exist at all. That medical heritage is also their main limitation: they were built to be simple and safe for dosing, not to capture the full picture of a healthy human body.

The formulas it uses

All four take height in inches and add weight above a 5-foot (60-inch) baseline. The calculator converts your height to inches automatically, whether you enter centimetres or feet and inches.

Devine (1974) — the clinical standard, widely used for drug dosing.
Men: IBW = 50 + 2.3 × (height_in − 60)
Women: IBW = 45.5 + 2.3 × (height_in − 60)

Robinson (1983) — a refinement of Devine.
Men: IBW = 52 + 1.9 × (height_in − 60)
Women: IBW = 49 + 1.7 × (height_in − 60)

Hamwi (1964) — popular with dietitians and in diabetes care.
Men: IBW = 48 + 2.7 × (height_in − 60)

Miller (1983) — the most conservative of the set, giving slightly lower figures.

Healthy BMI range for Indians

Because a single "ideal" number is rarely realistic, the calculator also shows a healthy weight range from the standard BMI band of 18.5–24.9. However, research shows that South Asians, including Indians, tend to carry more body fat and abdominal fat at a given BMI than many other populations. The World Health Organisation's Asia-Pacific guidelines therefore use lower cut-offs: a BMI of 23 and above is considered overweight and 25 and above is obese for people of Asian descent. So if you are Indian, treating roughly the lower-to-middle part of the displayed range as your sensible target is often more appropriate than aiming for the very top of the 24.9 band.

A worked example

Take a man who is 178 cm tall. That is 178 ÷ 2.54 ≈ 70.1 inches, or about 10 inches above the 60-inch baseline. Using Devine: 50 + 2.3 × 10 ≈ 73 kg. Robinson gives 52 + 1.9 × 10 ≈ 71 kg, and Hamwi gives 48 + 2.7 × 10 ≈ 75 kg. The formulas land within a few kilograms of each other, and the average is shown as the headline figure. Separately, a BMI range of 18.5–24.9 at 178 cm works out to roughly 59 kg to 79 kg — a much wider, more realistic band.

Tips

• Use the average across formulas as a rough centre point, not an exact goal.
• Pair the number with waist circumference. For Indians, a waist over 90 cm (men) or 80 cm (women) signals higher health risk regardless of weight.
• Track body composition (fat vs muscle), energy and blood markers — cholesterol and fasting blood sugar — rather than the scale alone.

Common mistakes

• Treating IBW as a strict target. A muscular person can sit well above their "ideal" weight and be perfectly healthy.
• Ignoring frame size. These formulas assume a medium build and do not adjust for small or large skeletal frames.
• Applying it to children or pregnant women. IBW formulas are validated only for non-pregnant adults.

This is a screening tool for general guidance, not medical advice. Always consult a qualified doctor or dietitian before making significant changes to your diet or weight.