BMI Calculator - Body Mass Index

Calculate your Body Mass Index (BMI) to assess if you're at a healthy weight. Our free BMI calculator works with both metric and imperial units and provides personalized health insights.

BMI Calculator

BMI Categories

Underweight< 18.5
Normal18.5 - 24.9
Overweight25.0 - 29.9
Obese≥ 30.0

BMI Quick Facts

BMI doesn't distinguish between muscle and fat
Athletes may have "high" BMI due to muscle mass
Best used as a general screening tool
Consult healthcare provider for personalized advice

What You Need to Know About BMI

BMI Basics (In Plain English)

BMI is basically a quick way to see if your weight makes sense for your height. Think of it as a starting point - not the final answer. It takes your weight and height, does some math, and gives you a number that puts you in a category.

The formula? BMI = weight (kg) ÷ height (m)² - but don't worry, our calculator does the math for you. It's been around since the 1800s, so it's definitely not new.

Where BMI Falls Short

  • • Can't tell muscle from fat (bodybuilders often show as "overweight")
  • • Doesn't work great for very athletic people
  • • Ignores where you carry your weight
  • • Less reliable for older adults or certain ethnic backgrounds
  • • Bone density? BMI doesn't care about that either

What Your BMI Category Actually Means

Underweight (Under 18.5)

Might mean you're not eating enough, or could signal an underlying health issue. Worth checking with a doctor.

Normal (18.5-24.9)

The "sweet spot" where most health risks are lowest. But remember, it's just one piece of the puzzle.

Overweight (25.0-29.9)

Higher chance of heart problems and diabetes, but plenty of healthy people fall here too, especially athletes.

Obese (30.0+)

Significantly higher health risks. Definitely worth talking to a doctor about, but remember - you're more than just a number.

Questions People Actually Ask

Is BMI actually accurate for everyone?

Nope, not really. BMI works okay for average people, but it's pretty useless for athletes, bodybuilders, or anyone with more muscle than usual. If you're pregnant, elderly, or from certain ethnic backgrounds, take BMI with a grain of salt. Your doctor knows way more about your health than any number can tell you.

What's the "perfect" BMI?

Most health experts say 18.5 to 24.9 is the sweet spot, but honestly? There's no magic number. Some people feel amazing at 23, others feel their best at 26. Your ideal BMI depends on your body type, muscle mass, and how you actually feel day to day.

How often should I check my BMI?

Once a month is plenty - your BMI doesn't change overnight. If you're trying to lose or gain weight, maybe check more often, but don't obsess over tiny daily changes. Your weight naturally fluctuates based on water, food, hormones, and even the time of day you step on the scale.

My BMI says I'm overweight - now what?

First, don't panic. BMI is just one data point. If you're concerned, chat with your doctor or a dietitian who can look at the bigger picture. Focus on building healthy habits - eating well, moving more, sleeping better. The number will follow if it needs to, but your health is about so much more than BMI.