Ideal Body Weight: How to Calculate It, With Five Formulas and an Indian Height-Weight Chart

Your ideal body weight is a range, not a single number, and different formulas give different answers. The four classic formulas (Devine, Robinson, Miller and Hamwi) use only height and sex. The BMI method gives a range based on a healthy BMI for your height. For a man of 172 cm, the four height formulas land between about 67 and 69 kg, while the Indian BMI method gives 55 to 68 kg. All of these are reasonable. None of them knows how much of your weight is muscle.

This guide shows each formula with its arithmetic, compares them for the same people, and gives you a simple chart for Indian heights. It also explains how to use the numbers without letting them become an obsession.

What "ideal weight" really means

The formulas were not designed to tell you how you should look. Most were developed in the 1950s to 1980s for practical purposes: Devine's 1974 formula was proposed to help dose certain medicines, and later versions adjusted it. They estimate a weight associated with good health and survival for an average adult of your height.

They have well-known limits. They ignore your frame size, muscle mass, bone density, age and ethnicity. A muscular person can be well above "ideal" and perfectly healthy. A person with low muscle and a big belly can sit right at the ideal weight and still have metabolic risk. So think of the number as a rough orientation point, and look at waist and body fat alongside it.

Formula 1: Devine (1974)

The most widely used.

• Men: 50 kg + 2.3 kg for every inch over 5 feet
• Women: 45.5 kg + 2.3 kg for every inch over 5 feet

Example: a man, 172 cm

172 cm is 67.7 inches, which is 7.7 inches over 5 feet. Ideal weight = 50 + (2.3 × 7.7) = 50 + 17.7 = 67.7 kg.

Example: a woman, 158 cm

158 cm is 62.2 inches, 2.2 inches over 5 feet. Ideal weight = 45.5 + (2.3 × 2.2) = 45.5 + 5.1 = 50.6 kg.

Formula 2: Robinson (1983)

• Men: 52 kg + 1.9 kg per inch over 5 feet
• Women: 49 kg + 1.7 kg per inch over 5 feet

Man, 172 cm: 52 + (1.9 × 7.7) = 52 + 14.6 = 66.7 kg. Woman, 158 cm: 49 + (1.7 × 2.2) = 49 + 3.7 = 52.7 kg.

Formula 3: Miller (1983)

• Men: 56.2 kg + 1.41 kg per inch over 5 feet
• Women: 53.1 kg + 1.36 kg per inch over 5 feet

Man, 172 cm: 56.2 + (1.41 × 7.7) = 56.2 + 10.9 = 67.1 kg. Woman, 158 cm: 53.1 + (1.36 × 2.2) = 53.1 + 3.0 = 56.1 kg.

Formula 4: Hamwi (1964)

• Men: 48 kg + 2.7 kg per inch over 5 feet
• Women: 45.5 kg + 2.2 kg per inch over 5 feet

Man, 172 cm: 48 + (2.7 × 7.7) = 48 + 20.8 = 68.8 kg. Woman, 158 cm: 45.5 + (2.2 × 2.2) = 45.5 + 4.8 = 50.4 kg.

Formula 5: the BMI range method

This one gives a range, which is more honest. Choose a healthy BMI range, then work out the weight at each end:

Weight = BMI × (height in metres)²

The international healthy range is a BMI of 18.5 to 24.9. For Asian Indians, a healthier range is 18.5 to 22.9, because risk of diabetes and heart disease rises at lower BMI in South Asians (Misra and Shrivastava, Nutrients, 2013). A BMI of 23 to 24.9 is considered overweight on the Asian Indian scale.

Example: a man, 172 cm

(1.72)² = 2.9584 Lower end: 18.5 × 2.9584 = 54.7 kg Upper end (Indian): 22.9 × 2.9584 = 67.7 kg Upper end (international): 24.9 × 2.9584 = 73.7 kg

So an Indian healthy range is about 55 to 68 kg.

Example: a woman, 158 cm

(1.58)² = 2.4964 Lower: 18.5 × 2.4964 = 46.2 kg Upper (Indian): 22.9 × 2.4964 = 57.2 kg

Range: about 46 to 57 kg.

Comparing the formulas

| Person | Devine | Robinson | Miller | Hamwi | BMI range (Indian) | |---|---|---|---|---|---| | Man, 172 cm | 67.7 | 66.7 | 67.1 | 68.8 | 54.7 to 67.7 | | Woman, 158 cm | 50.6 | 52.7 | 56.1 | 50.4 | 46.2 to 57.2 | | Man, 180 cm | 75.0 | 72.6 | 71.5 | 77.3 | 59.9 to 74.2 | | Woman, 165 cm | 56.9 | 57.4 | 59.8 | 56.4 | 50.4 to 62.3 | | Man, 165 cm | 61.4 | 61.4 | 63.2 | 61.4 | 50.4 to 62.3 | | Woman, 150 cm | 43.3 | 47.4 | 51.8 | 43.4 | 41.6 to 51.5 |

(All weights in kilograms.)

Notice that the height formulas for short women vary a lot (43 to 52 kg for 150 cm). That's because the formulas extrapolate from a base of 5 feet and were built on taller populations. They tend to overshoot reliability at both ends of the height range.

Ideal weight chart for Indians (BMI 18.5 to 22.9)

| Height | Healthy weight range (kg) | |---|---| | 4 ft 10 in (147 cm) | 40 to 50 | | 5 ft 0 in (152 cm) | 43 to 53 | | 5 ft 2 in (157 cm) | 46 to 57 | | 5 ft 4 in (163 cm) | 49 to 61 | | 5 ft 6 in (168 cm) | 52 to 64 | | 5 ft 8 in (173 cm) | 55 to 68 | | 5 ft 10 in (178 cm) | 58 to 72 | | 6 ft 0 in (183 cm) | 62 to 77 |

Use this chart as a screen, not a target. If you're 5 ft 6 in and weigh 66 kg, you're a couple of kilos above the Indian range but you might also be strong and fit. Check your waist and body fat before deciding anything.

How to find your own range in 60 seconds

1. Convert your height to metres and square it. (If you are 1.68 m: 1.68 × 1.68 = 2.82.)
2. Multiply by 18.5 for the lower end: 2.82 × 18.5 = 52.2 kg.
3. Multiply by 22.9 for the upper end: 2.82 × 22.9 = 64.6 kg.
4. Your Indian healthy range is 52 to 65 kg.

Why "ideal" can mislead you

Muscle weighs more than fat

A strong person with a lot of muscle can be well above their "ideal weight" and have excellent health markers. Use body fat percentage and waist to decide.

The thin-fat person

Someone at their "ideal" weight with low muscle and a big belly isn't metabolically ideal. This is common in India. Their blood sugar, liver enzymes or triglycerides can be abnormal at a normal weight.

Age

Some weight gain after 50 or 60 is not necessarily harmful, and in older adults a slightly higher BMI is sometimes protective, because it comes with more reserves. Very low weight in old age is linked to higher risk of falls, infections and poor recovery. Don't push an elderly parent toward a young person's ideal weight without medical advice.

Frame size

People with small, medium or large frames can differ by several kilos at the same height. Doctors sometimes estimate frame size from wrist circumference or elbow breadth.

Medical conditions

Fluid retention in heart, kidney or liver disease, thyroid problems, PCOS and some medicines can change weight in ways that have nothing to do with ideal weight formulas.

Using ideal weight for medicines

Devine's formula is still used in hospitals to estimate dosing for some medicines and to size ventilator settings, particularly in people who are very overweight, because certain drugs distribute in lean tissue. If your doctor asks your "ideal body weight", this is likely the one they mean.

What to do if you're above the range

• Don't aim to hit the top of the chart in a month.
• A loss of 5 to 10 percent of body weight brings real improvements in blood sugar, blood pressure, cholesterol and joint pain.
• Aim for about 0.5 kg a week.
• Include protein at each meal and some strength training so that what you lose is mostly fat.
• Get fasting glucose, lipids, liver and thyroid checked.

What to do if you're below the range

• Don't assume it's fine. Underweight in India is common and linked to anaemia, weak bones and poor immunity.
• Look for causes: poor appetite, thyroid overactivity, diabetes, chronic infection such as tuberculosis, digestive disease or stress.
• Build weight with strength training, regular meals and calorie-dense, nutritious foods like nuts, ghee, paneer, eggs, dal and full-fat curd.

Frequently asked questions

How to calculate ideal body weight by height?

Use the Devine formula for a quick answer, or multiply your height in metres squared by 18.5 and 22.9 to get a healthy range for Indians.

What is the ideal weight for a 5 ft 6 in Indian man or woman?

Around 52 to 64 kg for a BMI of 18.5 to 22.9. Individual factors like muscle and frame can shift this.

Which ideal body weight formula is the most accurate?

None is clearly the best. Devine is the most commonly used clinically. The BMI range method is more flexible and better suited to Indians.

What is the difference between ideal and healthy weight?

Ideal weight is a single estimate from a formula. Healthy weight is a range in which health risks are lowest. The range is more useful.

Is ideal body weight the same for men and women?

No. The formulas have different starting points for men and women, reflecting average differences in muscle and frame.

Can I be healthy outside my ideal weight?

Yes, especially if you have a lot of muscle. Check your waist, blood pressure, blood sugar and cholesterol.

When to see a doctor

If you're far above or below your range, if your weight has changed by more than 5 percent in six months without trying, or if you have swelling, tiredness, constant thirst, palpitations or irregular periods, see a doctor.

Care at Prakash Hospital Noida

Whether you live in Sector 18, Sector 62, Greater Noida West, or anywhere nearby, Prakash Hospital Noida is a trusted name for weight management and general health in Noida. Our physicians can help you work out a realistic target weight and the steps to reach it safely.

To book a consultation, call the number.

Sources: Devine BJ. Gentamicin therapy. Drug Intelligence and Clinical Pharmacy, 1974. Robinson JD et al., 1983; Miller DR et al., 1983; Hamwi GJ, 1964 (ideal weight formulas). Misra A, Shrivastava U. Obesity and dyslipidemia in South Asians. Nutrients, 2013.

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