BMI Calculator - Calculate Your Body Mass Index
Get your BMI result in seconds. Simple, accurate, and free forever.
Calculate Your BMI
What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
How to Use This Calculator
Simply enter your height and weight, choose your preferred units (metric or imperial), and click calculate. Your BMI result will appear instantly along with your weight category and personalized recommendations.
Who Should Use This?
This calculator is designed for adults aged 18 and over. For children and teens, BMI is interpreted differently using age-specific percentiles. We offer specialized calculators for children, teens, and athletes.
⚠️ BMI is a screening tool, not a diagnostic. It doesn't account for muscle mass, bone density, or fat distribution. Always consult a healthcare provider for personalized health advice.
How to Use This BMI Calculator
Using our calculator couldn't be easier. Here's what you need to do:
- Choose your units: Pick either metric (kilograms and centimeters) or imperial (pounds and inches). Whatever you're comfortable with!
- Enter your height: Type in your height. If you're using metric, that's in centimeters (like 175 cm). For imperial, use inches (like 69 inches).
- Enter your weight: Add your weight in kilograms or pounds, depending on what you selected.
- Get your results: Hit that calculate button and boom - your BMI appears instantly along with what category you fall into.
The calculator does all the math for you. No need to remember formulas or grab a calculator - we've got you covered.
Pro Tip: For the most accurate results, weigh yourself in the morning before breakfast, and measure your height without shoes. Small differences don't matter much, but if you want to track changes over time, consistency helps!
Understanding Your BMI Score
Once you get your number, you might be wondering what it actually means. Let me break it down for you in simple terms.
The BMI Categories
Your BMI score puts you into one of these groups:
- Below 18.5 - Underweight: This suggests you might not be carrying enough weight for your height. Could be perfectly normal for some people, but worth checking with a doctor to make sure you're getting proper nutrition.
- 18.5 to 24.9 - Normal Weight: This is considered the healthy range where most people tend to have lower health risks. If you're here, you're doing something right! Keep it up.
- 25 to 29.9 - Overweight: You're carrying some extra pounds, which is super common. This range might increase certain health risks, but it's not a crisis. Many people in this range are perfectly healthy and active.
- 30 to 34.9 - Obese Class I: This level of obesity can increase risks for conditions like diabetes and heart disease. But here's the good news - even small weight losses can make a real difference to your health.
- 35 to 39.9 - Obese Class II: At this level, health risks become more significant. Working with healthcare professionals can help you develop a safe plan to improve your health.
- 40 and Above - Obese Class III: This is sometimes called severe obesity. It's definitely time to work closely with doctors, but don't lose hope - people successfully improve their health from this range all the time.
What BMI Doesn't Tell You
Here's something important: BMI is useful, but it's not perfect. It can't tell the difference between fat and muscle. So if you're a bodybuilder or serious athlete, your BMI might say you're overweight when you're actually super fit. It also doesn't account for where you carry your weight, which matters for health.
That's why we created specialized calculators for athletes, men, women, and other groups who might need different interpretations.
What to Do After Calculating Your BMI
Got your number? Now what? Here's my advice based on what healthcare professionals recommend:
If You're in the Normal Range
Awesome! But don't just pat yourself on the back and move on. The goal is to stay here. Keep doing what you're doing - eating reasonably well, staying active, getting enough sleep. Calculate your BMI once or twice a year to make sure you're on track.
If You're Underweight
First, don't panic. Some people are naturally thin. But if you've lost weight recently or you're trying to gain, talk to your doctor. They can check if there's an underlying issue and help you build healthy weight gain habits. Focus on nutritious, calorie-dense foods rather than just eating junk.
If You're Overweight or Obese
Okay, this might not be the result you wanted, but it's actually useful information. Knowing is the first step to making positive changes. Don't try crash diets or extreme measures - they rarely work long-term and can mess with your metabolism.
Instead, think about small, sustainable changes:
- Add more vegetables to your meals (they fill you up with fewer calories)
- Find physical activities you actually enjoy (dancing, hiking, swimming - it doesn't have to be a gym)
- Pay attention to portion sizes (our portions have gotten huge over the years)
- Get enough sleep (tired people tend to eat more and make worse food choices)
- Track your progress (but not obsessively - check in monthly, not daily)
Check out our weight loss tips for more practical advice that actually works in real life.
Important: If your BMI is 30 or above, definitely schedule an appointment with your doctor. They might want to check for related health conditions and can provide personalized guidance. Don't try to handle this alone - medical support makes a huge difference.
Frequently Asked Questions
How accurate is BMI?
BMI is pretty accurate for most people as a general screening tool. It works well for average adults who aren't super muscular or athletes. For about 70-80% of people, BMI gives a good indication of body fat levels. But it has limitations - check our BMI accuracy page for the full scoop.
Should I calculate BMI daily?
Nope! Your weight fluctuates day to day (water retention, when you last ate, all that stuff). Checking daily will just drive you crazy. Once a month is plenty, or every few months if you're just monitoring. Focus on how you feel and how your clothes fit - those matter too.
Is BMI different for men and women?
The formula is the same, but women naturally have higher body fat percentages than men at the same BMI. Our women's BMI calculator and men's BMI calculator provide gender-specific guidance and interpretations.
Can I use this if I'm pregnant?
BMI calculations during pregnancy aren't very useful since you're supposed to gain weight! If you're planning to get pregnant, calculating your pre-pregnancy BMI can be helpful, but talk to your OB-GYN about appropriate weight gain during pregnancy.
My BMI says I'm overweight but I feel healthy. Should I worry?
BMI is just one indicator. If you eat well, exercise regularly, and your doctor says your health markers (blood pressure, cholesterol, blood sugar) are good, you might be one of those people who's healthy at a higher BMI. Bodies are diverse! Still worth discussing with your doctor, but don't stress too much over the number alone.
Other Calculators You Might Find Useful
Depending on your situation, these specialized calculators might give you more relevant information:
- BMI Calculator for Adults - Standard BMI calculation with detailed adult-specific guidance
- BMI Calculator for Children - Age and gender-adjusted BMI for kids
- BMI Calculator for Teens - Adolescent growth patterns considered
- BMI Calculator for Athletes - Adjusted for higher muscle mass