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BMI Calculator

Calculate your Body Mass Index (BMI) and find out if you are at your ideal weight, underweight or overweight. Includes interpretation according to WHO standards.

Optional
Note: For children and adolescents (2-19 years), fill in the age for a more precise evaluation based on WHO percentiles.
BMI Classification Table
Classification BMI (kg/m²) Description
Severe Thinness < 16 Very high risk of health problems
Moderate Thinness 16 - 16,9 High risk of health problems
Mild Thinness 17 - 18,4 Below ideal weight, moderate risk
Normal Weight 18,5 - 24,9 Adequate and healthy weight
Overweight 25 - 29,9 Excess weight, moderate risk
Obesity Grade I 30 - 34,9 Mild obesity, significant risk
Obesity Grade II 35 - 39,9 Severe obesity, serious risk
Obesity Grade III ≥ 40 Morbid obesity, very serious risk
Important for adults:

BMI is a general measure that does not account for body composition (muscle vs fat). It may not be accurate for:

  • Athletes or very muscular people
  • Elderly people with muscle loss
  • Pregnant or breastfeeding women

Always consult a healthcare professional for a complete evaluation.

Note: For children and adolescents (2-19 years), we use the percentile system instead of fixed BMI values. Percentiles compare the child's BMI with others of the same age and gender.
Classification Percentile Description
Underweight < P5 BMI below the 5th percentile for age and gender
Healthy Weight P5 - P85 BMI between percentile 5 and 85 - adequate weight
Overweight P85 - P95 BMI between percentile 85 and 95 for age and gender
Obesity ≥ P95 BMI equal to or above the 95th percentile
Average BMI Values by Age (kg/m²)
How to use this table: Compare the child's BMI with the values below for their age and gender. The P50 value represents the ideal average BMI.
Boys
Age P5 P50 P85 P95
2 years14.516.517.518.3
3 years14.315.917.218.1
4 years14.015.516.917.8
5 years13.815.316.817.9
6 years13.815.316.918.0
7 years13.715.417.218.6
8 years13.715.617.819.3
9 years13.716.018.420.0
10 years13.916.419.021.0
11 years14.016.919.721.8
12 years14.417.520.422.8
13 years14.818.121.223.7
14 years15.318.822.024.5
15 years15.819.422.625.2
16 years16.320.023.225.9
17 years16.720.523.726.4
18 years17.020.924.226.8
19 years17.321.224.527.2
Girls
Age P5 P50 P85 P95
2 years14.216.217.318.2
3 years13.915.817.018.0
4 years13.715.416.817.8
5 years13.515.216.818.0
6 years13.415.217.018.4
7 years13.415.417.419.0
8 years13.515.818.019.9
9 years13.616.318.821.0
10 years13.816.919.622.0
11 years14.217.620.523.1
12 years14.618.421.524.2
13 years15.219.022.325.2
14 years15.719.623.026.0
15 years16.220.223.526.7
16 years16.520.524.027.2
17 years16.820.824.427.6
18 years17.021.024.728.0
19 years17.221.225.028.3
Legend:
  • P5: Lower limit of healthy weight
  • P50 (green): Ideal average weight for age
  • P85: Upper limit of healthy weight
  • P95: Start of obesity range
How to interpret percentiles:
  • Percentile 5: Only 5% of children have a lower BMI
  • Percentile 50: Average value - half above, half below
  • Percentile 85: 85% of children have a lower BMI
  • Percentile 95: 95% of children have a lower BMI
Important for children and adolescents:

BMI in children naturally varies with age and gender due to growth and development:

  • The percentile system compares the child with others of the same age and gender
  • We use the growth charts from the WHO (World Health Organization)
  • It is normal for BMI to vary during growth
  • Always fill in the age for an accurate evaluation

For children, it is especially important to consult a paediatrician for a complete assessment of growth and development.