What is BMI?
Body Mass Index (BMI) is a number that estimates whether your weight is in a healthy range for your height. It's calculated from just two values — weight and height — which makes it easy to use as a quick screening tool.
BMI doesn't measure body fat directly and doesn't distinguish muscle from fat, but for most adults it's a reasonable starting point for understanding where you stand and what to do next.
BMI categories
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Normal | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese | 30.0 or more |
How is BMI calculated?
BMI = weight (kg) / height (m)². Convert pounds to kilograms by dividing by 2.205, and inches to meters by multiplying by 0.0254. The calculator above does this for you automatically.
BMI limitations
BMI doesn't distinguish fat from muscle. Athletes with a lot of muscle mass can show a high BMI without being overweight. Pregnant women, the elderly, and people with very different body proportions also need other measures alongside BMI.
BMI thresholds were developed primarily on European populations. Some clinical guidelines suggest lower thresholds for people of South or East Asian descent. Treat your BMI as a starting point, not the final word.
Where to go from here
If your BMI is above 24.9, a moderate calorie deficit is the place to start — see our calorie deficit calculator for a daily target. If it's in the healthy range, focus on consistency over numbers — a simple food diary beats restrictive plans for staying on track.
What to do with your BMI result
Try Nuvvoo. Track meals by chatting, get an AI meal plan, and stay in your healthy range — without logging anything.
Frequently Asked Questions
What is a healthy BMI?
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A BMI between 18.5 and 24.9 is considered healthy for most adults. Outside this range doesn't automatically mean a health problem — it just means it's worth a closer look with a clinician.
How do I calculate my BMI?
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BMI is your weight in kilograms divided by your height in meters squared (kg/m²). For pounds and inches, divide pounds by inches squared and multiply by 703. The calculator above handles the math.
Is BMI accurate?
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BMI is a useful screening tool but it isn't a direct measure of body fat. It doesn't account for muscle mass, bone density, or body composition, so athletes and older adults often need additional measures.
What BMI is considered overweight?
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A BMI of 25.0 to 29.9 is classified as overweight. A BMI of 30 or higher is classified as obese.
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