BMI Calculator (kg & cm)
Work out your BMI from your weight in kilograms and your height in centimetres. Free, private, and your measurements are not uploaded.
—
below 18.5Healthy range
18.5–24.9Overweight
25–29.9Obesity
30+
100% Private
Your height and weight are calculated in your browser — your measurements are not sent to a server.
Instant
Get your result the moment you press Calculate.
Free & Unlimited
No account and no limits on how often you use it.
How to calculate your BMI
Three quick steps. Nothing to install and nothing leaves your device.
Pick your units
Choose kilograms or pounds, and centimetres or feet and inches.
Enter weight and height
Type your measurements. Imperial values are converted automatically.
Calculate
See your BMI, its category and a reference weight range for your height.
Metric BMI Calculator and Imperial BMI Calculator
Use kilograms and centimetres, or pounds, feet and inches.
Metric BMI calculator (kg and cm)
Formula: BMI = weight (kg) ÷ height (m)². For example, 70 kg at 175 cm (1.75 m) gives a BMI of about 22.9.
Imperial BMI calculator (lbs, ft and in)
Formula: BMI = 703 × weight (lb) ÷ height (in)². For example, 154 lb at 5 ft 9 in (69 in) gives a BMI of about 22.7.
About BMI
What the number means and what it does not.
How is BMI calculated?
For adults, BMI is calculated by dividing weight in kilograms by height in metres squared. This tool converts imperial measurements automatically.
Adult BMI categories
For adults aged 20 and older, commonly used screening categories are: underweight below 18.5, healthy weight 18.5–24.9, overweight 25–29.9, and obesity 30 or above.
Important note
BMI is a screening measure, not a diagnosis. It does not directly measure body fat and may not describe health accurately for every person. Adult categories are not intended for children or teens, whose BMI is interpreted using age- and sex-specific percentiles. If you have concerns about your weight or health, consult a qualified healthcare professional.
Metric BMI calculator: kg and cm
Choose Kilograms (kg) and Centimetres (cm), type your weight and height and press Calculate BMI. The calculator shows your BMI to one decimal place, your adult category and a reference weight range for your height.
- The formula. BMI = weight (kg) ÷ height (m)². Your height in centimetres is divided by 100 to get metres.
- Example. 70 kg at 175 cm (1.75 m) gives a BMI of about 22.9.
- Accepted values. Height from 50 to 260 cm and weight up to 500 kg. Anything outside that shows an error message.
- Mixed units are fine. Weight and height units are chosen separately, so you can pick pounds for weight and still enter height in centimetres.
- Adults only. The categories are for people aged 20 and older, and they are not meant for use during pregnancy.
Categories follow the adult BMI ranges used by the CDC and WHO. BMI is a screening measure, not a diagnosis.
More BMI options
Why check your BMI?
BMI is one of the quickest ways to relate your weight to your height. It is widely used by doctors, health organizations and researchers as a first-step screening tool, because it needs only two measurements and no special equipment.
- A quick starting point. Your BMI shows at a glance whether your weight falls in the underweight, healthy, overweight or obesity range for adults.
- A weight range for your height. Along with your BMI, this calculator shows the span of weights that would fall in the 18.5–24.9 range at your height, so you can see where you sit.
- Track change over time. Recalculate after a change in weight to see how your BMI has moved, using the same units each time.
- A good conversation opener. A BMI result can help you decide what to ask a doctor, dietitian or trainer.
- Private by design. Your height and weight are calculated in your browser and never sent to a server.
Adult BMI chart
These standard categories apply to adults aged 20 and older. They are the same for men and women.
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight range |
| 25 – 29.9 | Overweight |
| 30 or above | Obesity |
To see how this looks at common heights, here are the approximate weights that fall in the 18.5–24.9 range:
| Height | In feet and inches | Weight range (kg) | Weight range (lb) |
|---|---|---|---|
| 160 cm | 5 ft 3 in | 47 – 64 kg | 104 – 141 lb |
| 170 cm | 5 ft 7 in | 53 – 72 kg | 118 – 159 lb |
| 180 cm | 5 ft 11 in | 60 – 81 kg | 132 – 178 lb |
| 190 cm | 6 ft 3 in | 67 – 90 kg | 147 – 198 lb |
Values are rounded. Use the calculator above for your exact height. A BMI in the healthy range does not guarantee good health, and a BMI outside it does not by itself mean poor health.
Using BMI sensibly
- Treat it as a screening tool, not a diagnosis. BMI cannot say how much of your weight is fat, muscle, bone or water.
- Athletes and very muscular people may have a BMI in the overweight range without excess body fat.
- Age and body type matter. Older adults and people with low muscle mass can carry more body fat than their BMI suggests.
- Look at more than one measure. Waist size, blood pressure, blood tests, diet, activity and family history all give a fuller picture.
- Measure carefully. Use barefoot height and a recent weight, ideally measured at the same time of day, for more consistent results.
- Not for children, teens or pregnancy. The adult categories here do not apply to people under 20 or to pregnant women.
- Talk to a professional. For personal advice about your weight or health, speak with a doctor or qualified healthcare professional. This tool is for information only.
Looking for other everyday calculators? Try the Age Calculator to find your exact age in years, months and days.
Frequently asked questions
Quick answers about the ConvertKit Lite BMI Calculator.
How do I use the imperial BMI calculator?
Choose Pounds (lb) as the weight unit and Feet and inches (ft / in) as the height unit, enter your measurements, then press Calculate BMI. The imperial formula is 703 × weight (lb) ÷ height (in)².
How do I use the metric BMI calculator?
Choose Kilograms (kg) and Centimetres (cm), enter your weight and height, then press Calculate BMI. The metric formula is weight (kg) ÷ height (m)².
Is my data stored or sent anywhere?
No. The calculation runs entirely in your browser, so your measurements are not uploaded to a server.
Can I mix metric and imperial units?
Yes. Weight and height units are chosen separately, for example pounds with centimetres.
Is BMI accurate for everyone?
BMI is a screening measure and does not directly measure body fat. It may not reflect health accurately for every person, such as athletes or older adults.
Can children and teens use this calculator?
No. The categories here are for adults aged 20 and older. For children and teens, BMI is interpreted using age- and sex-specific percentiles.
What is the reference weight range?
It is the weight span that would give an adult BMI of 18.5–24.9 at the height you entered. It is a guide, not a personal target.
What is a healthy BMI for adults?
For adults aged 20 and older, a BMI of 18.5 to 24.9 is the commonly used healthy weight range. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obesity.
Is the BMI formula different for men and women?
No. The adult BMI formula and category cut-offs are the same for men and women. Body composition can differ between people with the same BMI, which is one reason BMI is only a screening tool.
Why can BMI be misleading for athletes?
BMI uses only height and weight, so it cannot tell muscle from fat. A muscular person can have a BMI in the overweight range without having excess body fat.
Should I use BMI during pregnancy?
No. The adult categories are not designed for use during pregnancy. A doctor or midwife can advise on healthy weight changes during pregnancy.
Does this BMI calculator work on phones?
Yes. It works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux with nothing to install.
Is the BMI calculator free?
Yes. It is free with no account and no limit on how often you use it.
How do I convert centimetres to metres for BMI?
Divide by 100. A height of 175 cm is 1.75 m. The calculator does this for you.
What heights and weights does the metric calculator accept?
Height from 50 to 260 cm and weight up to 500 kg. Values outside these limits show an error message.