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BMI Calculator
Body Mass Index, or BMI, is the simplest way to check whether your weight is in a healthy range for your height. It is one number, calculated from your weight and height, and it places you in a category: underweight, healthy, overweight, or obese. Doctors and health organisations use it as a first screening step all over the world, because it needs only two measurements and no equipment beyond a scale and a tape measure. This free BMI calculator works in metric units (kilograms and centimetres) or US units (pounds, feet, and inches), so use whichever you are comfortable with. Enter your height and weight, and it shows your BMI, your adult category, and the healthy weight range for your height — the range of weights that would keep your BMI between 18.5 and 24.9. The page also explains the formula and the limits of BMI, because one number never tells the whole story about health. There is no sign-up, and your numbers are not stored.
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BMI: 24.2 — Normal weight
Healthy weight range for your height: 53.5 – 72.0 kg
Underweight < 18.5 · Normal 18.5–24.9 · Overweight 25–29.9 · Obese 30+. BMI is a guide, not a diagnosis.
How to use the BMI Calculator
- Choose metric (kg/cm) or US (lb/ft/in) units.
- Enter your height and weight.
- Read your BMI, category and healthy weight range.
BMI Calculator example
A person who weighs 70 kg and is 1.75 m tall has a BMI of about 22.9 — inside the healthy range of 18.5 to 24.9.
Who uses the BMI Calculator?
Adults checking their weight range, and students learning how BMI works.
About BMI Calculator
Check your BMI from weight in kg and height in cm, see your category and healthy weight range. Free BMI calculator for adults — fast, private, no sign-up. Everything runs in your browser, so your data stays private and results appear instantly. No signup and no payment — free to use.
What Is BMI?
BMI stands for Body Mass Index. It is calculated as weight in kilograms divided by height in metres squared: BMI = kg ÷ m². The idea is that weight alone means little — 70 kg is light for a tall person and heavy for a short one — so BMI adjusts weight for height and gives a single number that can be compared across people. A BMI of 22.9, for example, is in the healthy range whatever your exact height and weight are. Health organisations use BMI to screen large groups of people because it is quick, cheap, and consistent, and because, across a population, higher BMI is linked to higher risk of several health problems.
How to Check Your BMI (Step by Step)
Step 1: Choose metric (kg/cm) or US (lb/ft/in) units. Metric is the common choice in Pakistan and most of the world; US units are there if your scale shows pounds.
Step 2: Enter your height and weight. Measure your height without shoes, standing straight, and weigh yourself in light clothing. Small errors in height change the result more than small errors in weight, so measure height carefully.
Step 3: Read your BMI, category, and healthy weight range. The calculator shows your BMI to one decimal place, names your adult category, and gives the weight range that would put your BMI in the healthy band of 18.5 to 24.9.
BMI Categories and Healthy Weight Range
For adults, the standard categories are: underweight below 18.5, healthy (normal) from 18.5 to 24.9, overweight from 25 to 29.9, and obese at 30 and above. These cut-offs come from the World Health Organization and are used worldwide. The healthy weight range is the range of weights that keeps your BMI between 18.5 and 24.9 for your height — for a person 1.75 m tall, that is roughly 57 to 76 kg. The range is a guide, not a target: being anywhere inside it is fine, and the exact middle is not better than the edges. Note that these categories are for adults; children and teenagers use age-based BMI charts, not these cut-offs.
What BMI Does Not Tell You
BMI is a screening guide, not a diagnosis. It does not account for muscle mass: a muscular athlete can have a BMI over 25 while carrying very little body fat, because muscle is heavy. It does not account for where fat is stored, and belly fat carries more risk than fat elsewhere. It does not account for pregnancy, medical conditions, or age — older adults naturally carry more fat at the same BMI. And it says nothing about fitness, diet, blood pressure, or blood sugar. So use BMI as a starting point: if it is outside the healthy range, it is worth a conversation with a doctor, but it is not a verdict on its own. Never start a diet or an exercise plan based on BMI alone — talk to a doctor or a dietitian first.
Who Uses This Tool?
Adults use it to check their weight range quickly, before or after a doctor's visit. Students use it to learn how BMI works and to practise the formula. People starting a fitness or weight plan use it to set a sensible target range instead of guessing. Teachers and health workers use it to explain the idea to others. It is also used by anyone who has been told their BMI at a clinic and wants to understand what that number means.
Benefits of This Calculator
The first benefit is clarity: you get your BMI, your category, and your healthy weight range in one place, with the formula explained. The second is the unit choice — kg and cm for most users, pounds and feet/inches for those who need them. The third is privacy: your height and weight are not stored or sent anywhere. The fourth is the honest limits section: the page tells you what BMI cannot do, so you do not over-trust a single number. And it is free, with no sign-up, so checking takes seconds whenever you need it.
Worked Example
A person weighs 70 kg and is 1.75 m tall. First square the height: 1.75 × 1.75 = 3.0625. Then divide weight by that number: 70 ÷ 3.0625 = 22.86, which rounds to a BMI of about 22.9. That is inside the healthy range of 18.5 to 24.9. The healthy weight range for this height is from 18.5 × 3.0625 = about 56.6 kg up to 24.9 × 3.0625 = about 76.3 kg, so anywhere between roughly 57 and 76 kg keeps this person in the healthy band. Try it in the calculator: enter 70 kg and 175 cm, and check that your result matches 22.9. If you enter the same person as 80 kg instead, the BMI becomes about 26.1 — overweight — which shows how ten kilograms moves the category.
Frequently Asked Questions
What is BMI?
Body Mass Index is weight in kg divided by height in metres squared. It is a population-level guide that places you in a weight category for your height — not a diagnosis.
What are the adult BMI categories?
Underweight below 18.5, healthy (normal) 18.5–24.9, overweight 25–29.9, and obese 30 and above. These are the standard adult cut-offs used worldwide.
What is a healthy BMI?
A BMI between 18.5 and 24.9 is considered healthy for adults. For a person 1.75 m tall, that means roughly 57 to 76 kg. Being anywhere inside the range is fine.
What are the limitations of BMI?
BMI does not account for muscle mass, pregnancy, or medical conditions — it is a screening guide, not a diagnosis. A muscular person can have a high BMI while carrying little body fat.
Does BMI work for everyone?
No. It does not account for muscle mass, pregnancy, or medical conditions. The adult categories also do not apply to children and teenagers, who use age-based charts. Talk to a doctor before changing your diet or exercise based on BMI. Image alt text: "BMI Calculator — check your body mass index in kg and cm and see your healthy weight range, free" ---
Related guide
Learn more in our guide: BMI Calculator: What Your BMI Really Means — BMI is a simple number, but it is easy to misunderstand. Learn how BMI is calculated, what the categories mean, and why it is only a starting point for your health.
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