BMI calculator
Enter your height and weight; your body mass index, category and healthy range appear instantly.
Know the number, then act on it
NutriOS keeps your weight history and weekly trend, and sets daily calories for your goal.
How is BMI calculated?
BMI = weight (kg) / height² (m). For 1.70 m and 75 kg: 75 / (1.70 × 1.70) = 26.0.
What do BMI values mean?
| BMI | Category (World Health Organization) |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25–29.9 | Overweight |
| 30–34.9 | Obesity class I |
| 35–39.9 | Obesity class II |
| 40 and above | Obesity class III |
Limits of BMI
BMI does not separate muscle from fat; a muscular person can read as overweight. Older adults, pregnant women and under-18s need a different assessment. Waist size is a useful extra measure.
FAQ
What should my BMI be?
For adults 18.5 to 24.9 is considered healthy. The calculator also shows the weight range that matches it for your height.
Does BMI change with age?
Adult categories do not change with age. Under-18s are assessed with growth charts by age and sex; this calculator is for adults.
My BMI is high, what now?
Know your daily calorie needs first, then start with a small, sustainable deficit. If you have a chronic condition, talk to your doctor.