BMI Calculator

What your BMI result means

BMI divides weight by height squared to estimate whether you are underweight, in a healthy range, overweight, or obese. A score between 18.5 and 24.9 aligns with the World Health Organization's healthy range for most adults. Below 18.5 can signal underweight, while 25 and above indicates elevated health risks that grow as the number rises. Use BMI as a screening tool and pair it with other markers like waist size, activity levels, and how you feel day to day.

How we calculate BMI

• Metric units: We divide weight in kilograms by height in meters squared.
• Imperial units: We use pounds and inches with the standard 703 conversion factor.
• BMI Prime and category: The calculator also reports how far you are from a BMI of 25 and labels the category using WHO cutoffs.

Limitations to keep in mind

BMI cannot distinguish between muscle and fat. Athletes, lifters, and people with larger bone structures can score as overweight even with low body fat. Older adults sometimes show a normal BMI but higher fat percentage due to muscle loss. Treat BMI as a starting point and consider body composition, blood work, and guidance from a clinician before making big changes.

Improving your BMI safely

• Prioritize consistent sleep, hydration, and balanced meals rich in protein and fiber.
• Combine resistance training with daily movement to preserve muscle while changing weight.
• Use gradual calorie changes—about 250–500 calories per day—to avoid swings in energy or mood.
• Track progress weekly instead of daily to smooth out normal weight fluctuations.

When you are ready to act on your BMI result, BiteCheck can help you log meals with AI, set realistic weight targets, and see how your nutrition trends alongside your body measurements.