BMI for Age Calculator

BMI-for-age (also called BMI percentile) is used to assess weight status in children and adolescents aged 2–19. Because children grow rapidly and have different amounts of body fat at different ages, a standard adult BMI cut-off is inappropriate

The calculator uses the standard published formula for bmi age calc. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with kilograms, inches, square metres, watts. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: < 5th percentile = Underweight. Each step in the calculation is shown so you can verify the result manually.