Uses the Devine formula, a common medical reference point. It's a general guideline, not a precise target — body composition and frame size matter too.
What is an ideal weight calculator, and who needs it?
Ideal body weight is a reference figure for how much a person of a given height and gender might weigh. This calculator uses the Devine formula, which doctors have long used as a quick yardstick, and shows two results: a single ideal weight in kilograms and a range that runs 10% below to 10% above it.
It is useful for adults who are setting a realistic weight goal, people who have just checked their BMI and want a second reference, and anyone starting a diet or exercise routine who wants to know roughly where they stand. You only need your height in centimetres and whether to use the male or female version.
Formula used
- Height in inches = height in cm ÷ 2.54
- Inches over 5 feet = height in inches − 60 (never less than 0)
- Men: ideal weight (kg) = 50 + 2.3 × inches over 5 feet
- Women: ideal weight (kg) = 45.5 + 2.3 × inches over 5 feet
- Range = ideal weight × 0.9 to ideal weight × 1.1
Worked example
Take a man who is 170 cm tall. Height in inches = 170 ÷ 2.54 = 66.93, so he is 6.93 inches over 5 feet. Ideal weight = 50 + 2.3 × 6.93 = 65.9 kg. The range is 65.9 × 0.9 = 59.3 kg to 65.9 × 1.1 = 72.5 kg.
Now take a woman who is 160 cm tall. Height in inches = 160 ÷ 2.54 = 62.99, which is 2.99 inches over 5 feet. Ideal weight = 45.5 + 2.3 × 2.99 = 52.4 kg, with a range of 47.1 kg to 57.6 kg. Choose the matching gender, enter the height, and the calculator shows the same numbers.
Frequently asked questions
What is the Devine formula?
It is a simple medical formula from 1974 that estimates ideal body weight from height and gender. It starts at 50 kg for men or 45.5 kg for women at a height of 5 feet, then adds 2.3 kg for every inch above that.
Is the range shown the same as a BMI-based healthy range?
No. This calculator simply shows 10% below and 10% above the Devine result. A BMI-based range works differently. For a height of 170 cm, the Indian BMI band of 18.5 to 22.9 gives about 53.5 to 66.2 kg, so the upper end is lower than this tool's range. Use both as guides and talk to a doctor.
Why does my result not change when I enter a height below 152 cm?
The formula counts only the inches above 5 feet (152.4 cm). For anyone shorter, the calculator shows the starting values of 50 kg for men and 45.5 kg for women. For short adults, a BMI-based range is usually a better guide.
Can children and teenagers use this calculator?
No. It is designed for adults. Children and teenagers are still growing, and their healthy weight is judged on growth charts by age. Ask a paediatrician instead.
Should I try to reach my exact ideal weight?
Not necessarily. The result is a reference point, not a target. A muscular person or someone with a large frame can be healthy above it, and weight alone says little about fitness. Waist size, blood tests and how you feel matter as much.
Limitations and accuracy
The Devine formula uses only height and gender. It ignores age, muscle, bone structure and body fat, and it was not built around Indian or South Asian body types, who tend to carry more body fat at the same weight. The range is a simple 10% band, not a medical definition of healthy. The tool is meant for adults, and the result is fixed at its starting value for heights under 5 feet. This page is for general information only and is not medical advice.