BMI Calculator
BMI Calculator
Find your BMI in ten seconds. Then find out what it can't tell you.
One catch: BMI can't tell fat from muscle.
It only sees your height and your weight. To see what you're really made of, try the free body fat calculator, or let the ScanFit Body Scanner split your fat and muscle for you.
Estimate My Body FatBMI is your weight in kilograms divided by your height in metres squared. For adults, 18.5 to 24.9 is a healthy BMI, 25 to 29.9 is overweight, and 30 or higher is obesity. It can't tell fat from muscle, so treat it as a starting point, not a verdict.
Why Your BMI Is Still Worth Knowing
BMI isn't perfect, but it's the number your doctor looks at first. It's free, it takes seconds, and it means the same thing everywhere, which makes it a good place to start.
A result in the overweight or obesity range is linked to a higher risk of things like type 2 diabetes, high blood pressure and heart disease. So think of it as a nudge to look closer, not a verdict.
How BMI Is Calculated
It's your weight divided by your height squared. That's the whole trick.
- Metric: BMI = weight (kg) ÷ height (m)²
- Imperial: BMI = 703 × weight (lb) ÷ height (in)²
What Your Number Means
Could mean you're not getting enough fuel or nutrients. Worth a chat with your doctor.
The range linked to the lowest risk of weight-related health problems for most adults.
Risk starts to climb. Often a good moment to look at body fat, not just weight.
Linked to a higher risk of type 2 diabetes, high blood pressure and heart disease.
These are the standard adult categories used by the CDC and WHO. They don't apply to children or teens.
What Different BMI Ranges Can Look Like
Two people with the same BMI can look quite different, depending on muscle, where they carry fat, height and age. These examples are only a rough visual guide.
Healthy Weight By Height
Here's what the 18.5 to 24.9 range looks like in real weights. Find your height and see where you sit.
| Height | Healthy weight | ||
|---|---|---|---|
| 4' 10" | 147 cm | 89 to 119 lb | 40 to 54 kg |
| 5' 0" | 152 cm | 95 to 127 lb | 43 to 58 kg |
| 5' 2" | 157 cm | 101 to 136 lb | 46 to 62 kg |
| 5' 4" | 163 cm | 108 to 145 lb | 49 to 66 kg |
| 5' 6" | 168 cm | 115 to 154 lb | 52 to 70 kg |
| 5' 8" | 173 cm | 122 to 164 lb | 55 to 74 kg |
| 5' 10" | 178 cm | 129 to 174 lb | 58 to 79 kg |
| 6' 0" | 183 cm | 136 to 184 lb | 62 to 83 kg |
| 6' 2" | 188 cm | 144 to 194 lb | 65 to 88 kg |
| 6' 4" | 193 cm | 152 to 205 lb | 69 to 93 kg |
The same adult ranges apply to men and women, and they don't change with age. Rounded to the nearest pound or kilo.
How To Lower Your BMI
The only way to lower your BMI is to lose weight, and the goal is to lose fat, not muscle. Here's what works for most adults:
- Eat a small deficit. Aim for about 10 to 20% below the calories you burn. Our calorie calculator works out your number.
- Go slow. One to two pounds (0.5 to 1 kg) a week is the pace most health guidance recommends, and it's the pace people actually keep up.
- Eat enough protein and lift something. Two strength sessions a week help you keep muscle while the fat comes off.
- Walk more. A daily walk burns calories without making you hungrier the way hard cardio can.
- Sleep. Short nights make you hungrier and less likely to stick to the plan.
As a rule of thumb, one BMI point is roughly 5.5 to 8 lb (2.5 to 3.5 kg), depending on how tall you are. Check what the weight is made of too. A body fat percentage that falls while your muscle holds steady is the result you want.
What BMI Doesn't Tell You
Here's the problem. A person who lifts and a person who doesn't can weigh the same, stand the same height and get the same BMI, and look nothing alike. BMI can't see muscle. It can't see where your fat sits either, and that matters for your health.
It gets trickier when you're losing weight. Your BMI drops, and everyone says you look great, but it has no idea if the pounds coming off are fat or the muscle that keeps you toned.
That's why body composition, how much of you is fat and how much is lean mass, is the number worth tracking. Start with the body fat calculator.
See Your Fat And Muscle, Not Just One Number
BMI gives you one number from two measurements. The ScanFit Body Scanner gives you a lot more. Step on barefoot, hold the handle, and it reads your body from your hands to your feet, then splits it into:
- Body fat percentage
- Muscle mass
- Visceral fat
- Body water
Everything lands in the free ScanFit app, so you can watch your trend week by week instead of guessing from one weigh-in. Up to 10 people can share one scanner, it syncs with Apple Health, Garmin and Health Connect, and you get 100 days to try it. Don't love it? Send it back.
“I have started exercise routine and like how I can measure how well it’s working for me, measure my fat and muscle.”Diane, United States · Read on Trustpilot
See The Body Scanner Scanner + Food Scale Bundle
Not for anyone with a pacemaker or another implanted electronic device. If you're pregnant, check with your doctor first.
Frequently Asked Questions
What is a healthy BMI?
For adults, a BMI between 18.5 and 24.9 is considered a healthy weight. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obesity.
How can I lower my BMI?
Lose weight steadily by eating a small calorie deficit, about 10 to 20% below what you burn. Aim for 1 to 2 lb (0.5 to 1 kg) a week, eat plenty of protein, lift weights to keep muscle, walk daily and sleep well.
How much weight do I need to lose to drop one BMI point?
Roughly 5.5 to 8 lb (2.5 to 3.5 kg) for most heights. Taller people need to lose a little more per point, shorter people a little less.
What BMI is considered obese?
A BMI of 30 or higher. It's split into class 1 (30 to 34.9), class 2 (35 to 39.9) and class 3 (40 and above).
Is BMI the same for men and women?
The formula and the adult categories are the same. But at the same BMI, women usually carry more body fat than men, and body composition shifts with age, so the number doesn't tell the whole story.
Is BMI accurate for athletes?
Often not. Muscle is denser than fat, so someone who lifts can have a high BMI without carrying much body fat.
What's better than BMI?
Body fat percentage and waist size tell you more. A body composition scan goes further and measures fat and lean mass directly.
Does this work for kids?
No. It's built for adults 20 and over. Kids and teens are measured against age-and-sex percentile charts instead.
This calculator is for general information only and isn't medical advice. For questions about your health, weight or nutrition, talk to your doctor or a registered dietitian.