How to Calculate Ideal Body Weight Step by Step (India)

Many people in India step on a weighing scale, see a number, and wonder if it is right. Friends say one thing, a relative says another, and an online chart says something else. The good news is that you can work out a sensible target yourself in about ten minutes. This guide shows you how to calculate ideal body weight step by step, with simple maths, three worked examples from Indian homes, and the checks that keep the result useful.

You do not need a gym membership or a costly consultation to begin. All you need is a tape measure, a calculator and an honest reading of your current weight in kg. If you prefer to skip the arithmetic, a free body weight calculator on this site can do the steps for you in seconds.

What ideal body weight really means

Ideal body weight, often shortened to IBW, is an estimate of the weight at which a person of a given height and sex is most likely to enjoy good health. It was first used by doctors to decide medicine doses, and later became popular with people who wanted a weight goal. It is a guide, not a verdict.

Two points are worth remembering. First, IBW is a range in practice. A woman who is 160 cm tall may be healthy anywhere across a spread of around 11 kg. Second, the formulas were built mostly from studies of Western populations. Indians often carry more body fat at a lower BMI, so Indian guidance is stricter. The Indian consensus statement on obesity, which is widely followed by doctors in the country, treats BMI of 23 to 24.9 as overweight and 25 or above as obese. The healthy BMI band for Asian Indians is therefore 18.5 to 22.9.

Step by step: how to calculate ideal body weight

Step 1: Measure your height correctly

Stand barefoot with your back against a wall, heels together, eyes looking straight ahead. Place a flat book on your head and mark the wall. Measure from the floor to the mark in centimetres. Do this in the morning, because people are slightly taller after sleep. Write the number down, for example 170 cm.

Step 2: Convert height to inches

Most classic formulas use inches over 5 feet. Divide your height in cm by 2.54 to get inches. For 170 cm, the answer is 66.93 inches. Now subtract 60 inches, which is 5 feet. The result, 6.93 inches, is your height above 5 feet.

Step 3: Pick a formula

The four common formulas give slightly different answers, so choose one and stay with it, or take the average of two. Here they are in simple form, with weight in kg and inches counted above 5 feet.

Formula	Men (kg)	Women (kg)
Devine	50 + 2.3 per inch	45.5 + 2.3 per inch
Robinson	52 + 1.9 per inch	49 + 1.7 per inch
Miller	56.2 + 1.41 per inch	53.1 + 1.36 per inch
Hamwi	48 + 2.7 per inch	45.4 + 2.2 per inch

Step 4: Work out the BMI range for your height

This step adds the Indian view. Convert your height to metres, square it, and multiply by 18.5 and by 22.9. The two answers form your healthy weight range. This range is often more useful than a single formula result because it shows how much room you have.

Step 5: Compare and settle on a range

Place the formula answer next to the BMI range. If the formula answer sits inside the BMI range, you have a comfortable target. If it falls outside, trust the BMI range for planning, and then adjust for your muscle, age and health with a doctor’s help.

Worked India examples

Example 1: Rohit, 28, software tester in Pune

Rohit is 170 cm tall and weighs 78 kg. His height is 66.93 inches, so he is 6.93 inches over 5 feet. With the Devine formula, 50 + (2.3 x 6.93) gives about 65.9 kg. With Robinson, 52 + (1.9 x 6.93) gives about 65.2 kg. For the BMI range, 1.70 squared is 2.89. Multiply by 18.5 to get 53.5 kg, and by 22.9 to get 66.2 kg.

His working target is therefore about 65 to 66 kg, and he is roughly 12 kg above it. His current BMI is 78 divided by 2.89, which is 27, in the obese band for Indians. Rohit does not need to lose it all fast. A first goal of 72 kg in about four months, at around 0.5 kg a week, is realistic and safe.

Example 2: Meena, 34, school teacher in Jaipur

Meena is 155 cm tall and weighs 58 kg. Her height is 61.02 inches, only 1.02 inches over 5 feet. Devine gives 45.5 + (2.3 x 1.02), about 47.8 kg. Robinson gives 49 + (1.7 x 1.02), about 50.7 kg. Her BMI range is 1.55 squared, 2.4025, times 18.5 and 22.9, so 44.4 to 55.0 kg.

Her formula answers sit near the middle of the BMI range, so a target of 50 to 54 kg is sensible. She is about 4 kg above the top of the range, and her BMI is 24.1, in the overweight band. For Meena, small habit changes matter more than a hard diet. A daily 40 minute walk and fewer fried snacks in the evening could bring her into range within five or six months.

Example 3: Arjun, 45, bank officer in Lucknow

Arjun is 175 cm tall and weighs 70 kg. That is 68.90 inches, or 8.90 inches over 5 feet. Devine gives 50 + (2.3 x 8.90), about 70.5 kg. Hamwi gives 48 + (2.7 x 8.90), about 72.0 kg. The BMI range is 3.0625 times 18.5 and 22.9, which is 56.7 to 70.1 kg.

Arjun is already at the top edge of his range. His weight looks fine on paper, but his waist is 98 cm, and Indian guidance links a waist above 90 cm in men with higher risk of diabetes and heart disease. In his case the scale number is acceptable, yet the belly fat is a warning. He should aim for waist reduction rather than only weight loss.

Benefits of knowing your ideal weight range

• You get a clear, measurable goal instead of a vague wish to look slimmer.
• It helps you notice early weight gain before it becomes a health problem.
• It lets you plan calories and meals with a dietitian more accurately.
• It protects you from crash diets that promise impossible results.
• It gives families a common reference when children and elders gain or lose weight.

Challenges and limitations

No formula can see inside your body. Muscle weighs more than fat, so a regular weight trainer may look lean but be told to lose weight. Older adults often lose muscle and bone, so the same number can hide more fat than it did at 25. Body frame also matters, as a person with a small frame and a person with a large frame can differ by several kg at the same height.

The classic formulas also start from 5 feet, so they behave oddly for people below 150 cm, which includes many Indian women. For short people, the BMI range is the safer starting point. Pregnancy, thyroid problems, PCOS, diabetes and medicines such as steroids all change weight in ways a formula cannot predict. This is why every result should be treated as an estimate and not as medical advice.

Common mistakes to avoid

1. Using one number as a rule. A single figure such as 65 kg hides the fact that a range of several kg is normal.
2. Mixing units. Typing feet where centimetres are needed, or pounds instead of kg, ruins the answer.
3. Ignoring the Indian cutoffs. Western charts call BMI 24 normal, while Indian guidance already marks it as overweight.
4. Weighing at random times. Weight can swing by 1 to 2 kg during the day. Weigh yourself in the morning after using the toilet.
5. Copying someone else’s target. A friend with the same height may have a different frame, age and health history.
6. Chasing the number with crash diets. Very low calorie plans cause muscle loss and rebound gain.

Best practices for using your result

• Calculate with two methods and note the overlap, then use that as your target range.
• Measure your waist at the navel level every month along with weight.
• Aim to lose 0.25 to 0.5 kg a week, which is easier to hold for the long term.
• Build meals around the plate model in the ICMR-NIN Dietary Guidelines for Indians, with plenty of vegetables, dals, whole grains and limited oil, sugar and salt.
• Walk daily and add strength exercises twice a week, even at home with body weight moves.
• Review your target every six months, and after any major illness, pregnancy or change in activity.

What it costs to act on your number

Reaching a healthy weight need not be expensive. A walk in the park costs nothing, and home cooking with seasonal vegetables is cheaper than packaged food. A basic gym in a mid-sized Indian city often charges Rs. 800 to Rs. 2,000 a month. A registered dietitian may charge Rs. 500 to Rs. 2,500 per consultation, with many offering monthly plans. Government hospitals and many primary health centres run nutrition counselling for little or no fee, and the National Health Portal and the Ministry of Health and Family Welfare publish free guidance on healthy weight and diet.

Key takeaway: Treat ideal body weight as a healthy range worked out from your height, checked against the Indian BMI band of 18.5 to 22.9, and backed by waist size and a doctor’s advice.

Conclusion

Calculating ideal body weight is simple once you follow the steps. Measure your height, convert it to inches, apply a formula, find your BMI-based range, and compare. The examples of Rohit, Meena and Arjun show that the same method can lead to different advice, from steady weight loss to simple waist control. Keep your target realistic, keep it as a range, and update it as your life changes. For a quick check, you can read our guide on ideal body weight formulas explained with examples to see how each formula behaves at different heights.

Note: The calculator and this article give estimates only. They are not medical advice. Please consult a qualified doctor or dietitian before making big changes to your diet or exercise.

FAQs

What is a good weight for a 170 cm Indian man?
Using the Indian BMI band of 18.5 to 22.9, a man of 170 cm has a healthy range of about 53.5 to 66.2 kg. Formulas such as Devine and Robinson give about 65 to 66 kg. Within this range, the exact spot depends on muscle, age and waist size.

Which ideal body weight formula is best?
No single formula is best for everyone. Devine is the most widely used in clinics, while Robinson and Miller give slightly lower results for women. It is wise to compare two formulas and the Indian BMI range, then pick a target that overlaps.

Why do Indians have a lower BMI cutoff?
Studies on Asian Indians show more body fat, especially around the belly, at the same BMI as Western people. This raises the risk of diabetes and heart disease at lower weights. So Indian consensus guidance marks BMI 23 as overweight and 25 as obese.

Can I use these formulas if I am under 5 feet?
The formulas assume you are at least 5 feet tall, so results for shorter people can be unreliable. In that case, use the BMI-based range of 18.5 to 22.9 as your guide. A dietitian can help you refine it.

How fast should I lose weight to reach my ideal range?
A steady loss of 0.25 to 0.5 kg a week is generally considered safe for most adults. Faster loss often means muscle and water are leaving, not fat. People with health conditions should follow the plan set by their doctor.