Use this free BMI Calculator to check your body mass index, BMI category, healthy weight range, and BMI chart. Enter your height and weight to calculate your BMI instantly using kg, cm, lbs, stones, feet, or inches.
This Body Mass Index Calculator is useful for adults who want a quick BMI estimate, whether you are checking your BMI for men, BMI for women, healthy weight range, or general weight category.
BMI Calculator
Check your Body Mass Index using metric or imperial units.
What Is a BMI Calculator?
A BMI Calculator estimates your body mass index using your height and weight. BMI stands for Body Mass Index. It is commonly used as a simple screening tool to understand whether an adult may be in an underweight, healthy weight, overweight, or obesity range.
BMI does not directly measure body fat, muscle, bone density, fitness level, or overall health. It is only a general guide, so your result should not be treated as a medical diagnosis.
BMI Formula
The standard BMI formula is:
BMI = weight in kilograms ÷ height in metres squared
Example:
If your weight is 70 kg and your height is 1.75 m:
70 ÷ 1.75² = 22.86
Your BMI would be approximately 22.9.
BMI Categories for Adults
The general adult BMI chart is:
| BMI Result | Weight Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to 24.9 | Healthy weight |
| 25.0 to 29.9 | Overweight |
| 30.0 and above | Obesity |
These categories are general adult ranges. Your personal health can depend on many other factors, including age, muscle mass, waist measurement, activity level, medical history, and body composition.
BMI Calculator for Men and Women
This BMI Calculator can be used by adult men and women. The basic BMI formula is the same for both, because it compares body weight with height.
However, BMI does not show the difference between muscle and body fat. For example, a very muscular person may have a higher BMI even if they have a healthy body composition. This is why BMI should be used as a quick guide, not as the only measure of health.
BMI Calculator in KG and CM
If you use kilograms and centimetres, enter your weight in kg and height in cm. The calculator will convert your height into metres and calculate your BMI automatically.
Example:
Weight: 80 kg
Height: 180 cm
BMI = 80 ÷ 1.80²
BMI = 24.7
This result is within the general healthy weight range for adults.
BMI Calculator in Pounds, Stones, Feet and Inches
You can also calculate BMI using imperial measurements such as pounds, stones, feet, and inches. This is useful if your weight or height is recorded in UK or US measurement formats.
The calculator converts your height and weight into the correct values before calculating your body mass index.
How to Check My BMI
To check your BMI:
- Enter your weight.
- Enter your height.
- Choose the correct unit.
- Click calculate or view the instant result.
- Check your BMI number and category.
Your result will show your estimated BMI and the general adult category it falls into.
Healthy BMI Range
For most adults, a BMI from 18.5 to 24.9 is generally described as a healthy weight range.
A BMI below 18.5 may suggest underweight.
A BMI from 25 to 29.9 may suggest overweight.
A BMI of 30 or above may suggest obesity.
These ranges are only general guidelines. They should be understood alongside other health measurements and professional advice.
BMI Chart
A BMI chart helps you compare your height and weight with standard BMI categories. It can be useful if you want a quick visual guide to see where your BMI result sits.
BMI charts are helpful for general awareness, but they do not replace a full health check. For example, waist size, blood pressure, cholesterol, blood sugar, lifestyle, and family history can also matter.
BMI and Ideal Weight
BMI can help estimate whether your current weight is within a general healthy range for your height. However, it does not give a perfect ideal weight for every person.
Your ideal weight can vary depending on:
- Age
- Muscle mass
- Body shape
- Activity level
- Medical history
- Waist measurement
- Fitness goals
- Pregnancy status
- Ethnicity and personal health risk factors
For a more complete estimate, you may also want to use an ideal weight calculator, body fat calculator, or healthy weight calculator if available.
Why BMI Is Useful
BMI is useful because it is quick, simple, and easy to calculate. It can help adults get a general idea of their weight category without needing special equipment.
People often use BMI for:
- General health awareness
- Weight category checks
- Healthy weight planning
- Fitness tracking
- Body mass index comparison
- Weight loss progress monitoring
- Health and wellness goals
Limits of BMI
BMI has important limitations. It does not directly measure body fat or show where fat is stored on the body.
BMI may be less accurate for:
- Athletes
- Very muscular people
- Older adults
- Pregnant people
- Children and teenagers
- People with certain medical conditions
- People with different body compositions
For children and teenagers, BMI is assessed differently because age and growth patterns matter. Adults and children should not use the exact same BMI interpretation.
Should I Use BMI for Weight Loss?
BMI can be a useful starting point if you are trying to understand your weight category, but it should not be the only number you follow.
If your BMI is outside the healthy range, consider checking other health markers as well, such as waist measurement, blood pressure, activity level, nutrition, sleep, and medical advice.
Healthy changes should be realistic and safe. Avoid extreme diets or quick-fix plans.
Related Health Calculators
Use these related calculators to get a fuller picture of your health, weight, calories, and body composition:
Health Calculators
Browse all free health calculators on Calculators Arena, including BMI, calories, BMR, body fat, ideal weight, and water intake tools.
Calorie Calculator
Estimate how many calories you may need each day to maintain, lose, or gain weight based on your body details and activity level.
BMR Calculator
Calculate your basal metabolic rate to understand how many calories your body may burn at rest.
Body Fat Calculator
Estimate your body fat percentage using body measurements and compare it with general body composition ranges.
Ideal Weight Calculator
Check an estimated healthy weight range based on your height and body measurement method.
Water Intake Calculator
Estimate your daily water intake needs based on your weight, activity level, and lifestyle.
Frequently Asked Questions
What is a BMI Calculator?
A BMI Calculator estimates your body mass index using your height and weight. It helps place your result into a general adult weight category.
What does BMI stand for?
BMI stands for Body Mass Index.
How do I calculate BMI?
BMI is calculated by dividing weight in kilograms by height in metres squared.
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is generally considered within the healthy weight range.
Is BMI different for men and women?
The basic BMI formula is the same for adult men and women. However, BMI does not measure body fat, muscle mass, or body shape, so it should only be used as a general guide.
Is BMI accurate for athletes?
BMI may not be accurate for athletes or very muscular people because it does not separate muscle weight from fat mass.
Can children use this BMI Calculator?
This calculator is mainly for adults. Children and teenagers need age-based BMI interpretation, so a child or teen BMI tool should be used instead.
What is BMI 25?
A BMI of 25 is generally the starting point of the overweight category for adults.
What is BMI 30?
A BMI of 30 or above is generally classed within the obesity range for adults.
Is BMI a medical diagnosis?
No. BMI is a screening estimate, not a medical diagnosis. Speak to a qualified healthcare professional for personal health advice.
Disclaimer
This BMI Calculator is for general information and estimation only. It is not medical advice and should not be used to diagnose, treat, or manage any health condition. BMI is only one screening measure and may not reflect body fat, muscle mass, pregnancy, age-related changes, or individual health risks. For personal advice, speak to a qualified healthcare professional.