Height and weight
Two numbers decide the result. Height goes in as metres, squared, and weight as kilograms. A centimetre or two of height makes a visible difference, so measure rather than guess.
Free BMI calculator
BMI Calculator
Enter your height and weight and see your BMI, which WHO weight category it falls in, and the healthy weight range for your height — with the working shown, so you can check every number.
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24.2
BMI for 170 cm and 70 kg — Healthy weight
2 inputs
Height and weight
Screening tool
Not a diagnosis
Screening tool, not a diagnosis. BMI does not measure body fat directly, and it does not suit children, pregnant women, very muscular people or older adults. Talk to a doctor before acting on a result.
Calculate your BMI
170 cm · 70 kgExample figures are filled in. Replace them with your own measurements.
YOUR BODY MASS INDEX
WHO ADULT CATEGORIES
Your BMI
Healthy weight
CATEGORY
53.5 – 72.0 kg
HEALTHY WEIGHT FOR YOUR HEIGHT
Inside the healthy range
DISTANCE FROM HEALTHY RANGE
BMI 24.2 — Healthy weight (scale 15 to 40).
Your BMI at a glance
In the healthy range. A balanced diet and regular activity are the way to stay here.
BMI = 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2.
Healthy weight for 170 cm: 18.5 × 2.89 = 53.5 kg to 24.9 × 2.89 = 72.0 kg.
BMI is a screening tool, not a diagnosis. It does not measure body fat directly, and it does not suit children, pregnant women, very muscular people or older adults.
The categories are the World Health Organization's adult classification. For Indian readers, lower cut-offs apply — see the note below the category table.
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Understand the result
What does a BMI calculator do?
It turns two measurements — your height and your weight — into one number, the Body Mass Index. That number is then compared with the World Health Organization's adult weight categories, so you can see at a glance whether you are underweight, in the healthy range, overweight or obese. This calculator also works out the healthy weight range for your exact height, so you have a concrete target instead of just a label.
Underweight to obese
The World Health Organization sorts adult BMIs into underweight, healthy weight, overweight and obese, with obesity split into three classes. The bands are the same for men and women and for all adult ages.
BMI flags, it does not diagnose
BMI cannot tell muscle from fat, and it says nothing about where fat sits. A result outside the healthy range is a prompt to talk to a doctor, not a diagnosis on its own.
How it works
From height and weight to BMI
Measure in the morning, before eating, on the same scales each time. Then read the BMI together with the category and the healthy weight range for your height.
Pick a starting point, or enter your own figures
An average adult at 170 cm and 70 kg, a taller adult at 180 cm and 85 kg, or a shorter adult at 160 cm and 55 kg. Change any figure to match your own measurements.
Enter your height
In centimetres, or switch to feet and inches. The calculator accepts heights from 100 cm to 220 cm.
Enter your weight
In kilograms. The calculator accepts weights from 20 kg to 300 kg.
Read your BMI, category and healthy range
Your BMI to one decimal place, the WHO category, the healthy weight range for your height, and how far you are from that range — with the working shown underneath.
The calculation, explained
The BMI formula
BMI is your weight in kilograms divided by your height in metres, squared: BMI = weight (kg) ÷ height (m)². The categories are the World Health Organization's adult classification: below 18.5 is underweight, 18.5 to 24.9 is healthy weight, 25.0 to 29.9 is overweight, and 30.0 and above is obese. The healthy weight range for a height is the weight that gives a BMI of 18.5 at the low end and 24.9 at the high end.
1. Convert height to metres
170 cm = 1.70 m
Divide the height in centimetres by 100.
2. Square the height
1.70 × 1.70 = 2.89
Multiply the height in metres by itself.
3. Divide the weight by it
70 ÷ 2.89 = 24.2
The result is the BMI, shown to one decimal place.
A note for Indian readers: lower cut-offs apply
South Asians tend to develop diabetes and heart disease at lower BMIs than Europeans, so the WHO identifies lower public-health action points for Asian populations — 23 for overweight and 27.5 for obesity — and the Indian consensus guidelines (Misra et al., 2009) count 23.0–24.9 as overweight and 25 and above as obese, with a healthy range of 18.0–22.9. This calculator shows the WHO international categories as its main result; if you are of South Asian descent, treat a BMI from 23 upwards as a reason to talk to a doctor, even though the international table still calls it healthy weight.
Worked examples
Three BMIs, three categories
Select any example to load it into the calculator and check the working for yourself.
170 cm and 70 kg — healthy weight
At 170 cm and 70 kg, the BMI is 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2, which is in the healthy range. The healthy weight range for 170 cm is 53.5 to 72.0 kg, so 70 kg sits comfortably inside it — 2.0 kg below the top of the range.
BMI 24.2 · Healthy weight · Healthy range 53.5 – 72.0 kg
165 cm and 75 kg — overweight
At 165 cm and 75 kg, the BMI is 75 ÷ (1.65 × 1.65) = 75 ÷ 2.7225 = 27.5, which is overweight. The healthy weight range for 165 cm is 50.4 to 67.8 kg, so 75 kg is 7.2 kg above the top of the range.
BMI 27.5 · Overweight · Healthy range 50.4 – 67.8 kg
175 cm and 55 kg — underweight
At 175 cm and 55 kg, the BMI is 55 ÷ (1.75 × 1.75) = 55 ÷ 3.0625 = 18.0, which is underweight. The healthy weight range for 175 cm is 56.7 to 76.3 kg, so 55 kg is 1.7 kg below the bottom of the range.
BMI 18.0 · Underweight · Healthy range 56.7 – 76.3 kg
WHO adult BMI classification
BMI categories
The World Health Organization's adult classification, from the 1995 Technical Report Series No. 854. The bands are age-independent for adults and the same for both genders.
| BMI (kg/m²) | Category | What it means |
|---|---|---|
| Below 18.5 | Underweight | Possible nutritional deficiency; talk to a doctor if you have lost weight without trying. |
| 18.5 – 24.9 | Healthy weight | The range linked to the lowest health risk for most adults. |
| 25.0 – 29.9 | Overweight | Increased risk of type 2 diabetes, heart disease and joint problems. |
| 30.0 – 34.9 | Obese — Class I | Moderate health risk; a plan with a doctor is worth making. |
| 35.0 – 39.9 | Obese — Class II | Severe health risk; medical advice is recommended. |
| 40.0 and above | Obese — Class III | Very severe health risk; medical advice is strongly recommended. |
South Asians tend to develop diabetes and heart disease at lower BMIs than Europeans, so the WHO identifies lower public-health action points for Asian populations — 23 for overweight and 27.5 for obesity — and the Indian consensus guidelines (Misra et al., 2009) count 23.0–24.9 as overweight and 25 and above as obese, with a healthy range of 18.0–22.9. This calculator shows the WHO international categories as its main result; if you are of South Asian descent, treat a BMI from 23 upwards as a reason to talk to a doctor, even though the international table still calls it healthy weight.
Healthy weight for your height
Healthy weight for your height
The weight range that gives a BMI of 18.5 to 24.9 at each height — the WHO healthy range. Find your height and read across.
| Height | Healthy weight from | Healthy weight to |
|---|---|---|
| 150 cm | 41.6 kg | 56.0 kg |
| 155 cm | 44.4 kg | 59.8 kg |
| 160 cm | 47.4 kg | 63.7 kg |
| 165 cm | 50.4 kg | 67.8 kg |
| 170 cm | 53.5 kg | 72.0 kg |
| 175 cm | 56.7 kg | 76.3 kg |
| 180 cm | 59.9 kg | 80.7 kg |
| 185 cm | 63.3 kg | 85.2 kg |
| 190 cm | 66.8 kg | 89.9 kg |
A 10 cm difference in height moves the healthy range by about 6 kg. That is why the same weight can be healthy for one person and overweight for another — the number only makes sense against your own height.
Common mistakes
Four ways to read a BMI wrong
The BMI formula is short, but four readings trip people up. Each one can make a healthy result look worrying, or a risky one look fine.
Treating BMI as a diagnosis
BMI is a screening tool. It flags a result worth checking with a doctor; it does not by itself diagnose obesity, malnutrition or any disease. Blood pressure, blood sugar, cholesterol and waist size all matter alongside it.
Measuring height or weight wrong
Height in shoes adds a centimetre or two, and weight after a meal or on a different scale can shift by a kilogram. Both errors move the BMI. Measure height without shoes and weight in the morning, before eating, on the same scales.
Using the wrong units
The formula needs kilograms and metres. Entering pounds as kilograms, or centimetres as metres, gives a nonsense number. Use the feet-and-inches option if you think in imperial units, and let the calculator convert.
Chasing a single number
A BMI inside the healthy range is not a guarantee of health, and a BMI just outside it is not a disaster. Crash diets that force the number down fast rarely hold — steady habits, strength, sleep and waist size matter at least as much as the number itself.
Your questions, answered
BMI calculator FAQs
What is the BMI formula?
BMI = weight (kg) ÷ height (m)². Convert your height to metres first, square it, then divide your weight by that number. For 70 kg at 170 cm: 1.70 × 1.70 = 2.89, and 70 ÷ 2.89 = 24.2. In imperial units the same formula is BMI = (weight in pounds ÷ height in inches²) × 703.
What is a healthy BMI?
The World Health Organization calls 18.5 to 24.9 the healthy range for adults. For a height of 170 cm that means a weight of 53.5 to 72.0 kg. The healthy range is different for every height — check the table on this page for yours. For Indian adults, the Indian consensus guidelines use a narrower healthy range of 18.0 to 22.9.
What are the BMI cut-offs for Indians?
South Asians develop metabolic risk at lower BMIs, so lower cut-offs are used. The WHO identifies public-health action points of 23 for overweight and 27.5 for obesity in Asian populations, and the Indian consensus guidelines (Misra et al., 2009) count 23.0–24.9 as overweight and 25 and above as obese, with a healthy range of 18.0–22.9. This calculator's main result uses the WHO international bands; the note above explains the Indian cut-offs.
Is BMI accurate?
BMI is a useful screening tool, not a diagnosis. It cannot tell muscle from fat, so a very muscular person can score as overweight without excess body fat, and an older adult can score as healthy while carrying too much fat and too little muscle. It also says nothing about where fat sits — fat around the waist carries more risk than fat elsewhere. Treat the number as a starting point for a conversation with a doctor, not a verdict.
How do I convert feet and inches to centimetres?
Multiply the total inches by 2.54. For 5 ft 7 in: 5 × 12 + 7 = 67 inches, and 67 × 2.54 = 170.18 cm. At 70 kg that gives a BMI of 24.2 — the same as 170 cm. This calculator has a feet-and-inches option that does the conversion for you.
What should I do if my BMI is over 25?
First, check the measurement — height without shoes, weight in the morning. Then talk to a doctor, especially if your BMI is 30 or more, or if you have diabetes, high blood pressure or a family history of heart disease. Small, steady changes work best: a 5–10% weight loss over six months already lowers risk, and crash diets rarely hold.
Does BMI work for children?
No. Children's healthy weight changes with age and sex, so doctors use BMI-for-age percentile charts instead of the fixed adult bands. A child's BMI is plotted against other children of the same age and sex. This calculator is for adults only.
What is the difference between BMI and body fat percentage?
BMI is a ratio of weight to height — it never measures fat directly. Body fat percentage is the share of your weight that is fat, measured by skinfold calipers, bioelectrical impedance scales or a DEXA scan. Two people with the same BMI can have very different body fat percentages, which is why BMI is a screening tool and body fat percentage is a closer measure.
Does this calculator send my figures anywhere?
No. Your height and weight stay in your browser — the calculation runs entirely on this page, nothing is sent to a server, and reloading the page clears your recent checks. This tool is a screening aid, not medical advice; for advice about your own health, talk to a doctor.
About the method
This page uses the World Health Organization's BMI formula: BMI = weight (kg) ÷ height (m)², with the adult categories from the WHO Technical Report Series No. 854 (1995) — below 18.5 underweight, 18.5–24.9 healthy weight, 25.0–29.9 overweight, 30.0 and above obese, with obesity split into Class I (30.0– 34.9), Class II (35.0–39.9) and Class III (40.0 and above). The healthy weight range for a height is the weight that gives a BMI of 18.5 at the low end and 24.9 at the high end. BMI is shown to one decimal place; the healthy-range weights are shown to one decimal place. For feet and inches, 1 inch = 2.54 cm exactly.
The Indian cut-offs in the note are the WHO's lower public- health action points for Asian populations (23 for overweight, 27.5 for obesity) and the Indian consensus guidelines of Misra et al. (2009), which count 23.0–24.9 as overweight and 25 and above as obese, with a healthy range of 18.0–22.9. BMI is a screening tool, not a diagnosis, and it does not apply to children, who are assessed on BMI-for-age percentile charts.
Cross-checked 11 November 2026 against the ranking BMI calculators: 170 cm and 70 kg gives BMI 24.2 with a healthy range of 53.5–72.0 kg on calculatorplanet.in, and 78 kg at 1.72 m gives 26.4 on calkulator.in. Category thresholds follow the WHO Nutrition Landscape Information System and the CDC adult BMI categories.
Check another plan before you start
Try a different height or weight — or run the same check with the related tools for your other plans.