InfantChart
Share:

WHO Weight-for-Age Growth Chart (0-24 Months)

Plot your child's weight against WHO growth standards for ages 0-24 months. The chart displays standard percentile curves (3rd, 15th, 50th, 85th, 97th) with your child's measurement highlighted.

LMS Method: Z = ((X/M)^L - 1) / (L x S)

How It Works

This calculator uses WHO growth standards for monitoring weight in children from birth to 24 months. The WHO standards are based on the Multicentre Growth Reference Study (MGRS), which followed healthy breastfed children from six countries under optimal conditions. The LMS method (Lambda-Mu-Sigma) computes Z-scores and percentiles by comparing your child's weight to age- and sex-specific reference values.

Example Problem

A 6-month-old girl weighs 7.3 kg. What is her weight-for-age percentile?

  1. Enter the child's date of birth and measurement date (6 months apart).
  2. Select 'Girl' for gender.
  3. Enter 7.3 kg for weight.
  4. The calculator finds the LMS parameters for girls at 6 months and computes the Z-score.
  5. Result: approximately the 50th percentile, as 7.3 kg is near the WHO median weight for girls at 6 months.

Key Concepts

The WHO growth standards describe how children should grow under optimal conditions (breastfed, healthy, non-smoking households). A percentile indicates the percentage of children who weigh less than your child. Pediatricians look at growth trends over multiple visits — a child consistently at the 15th percentile who is growing steadily is usually healthy. Sudden drops or jumps across percentile lines may warrant further evaluation.

Applications

  • Well-child visits during the first 2 years
  • Monitoring growth of breastfed infants
  • Identifying potential failure to thrive early
  • Comparing growth across international populations
  • Nutritional counseling for new parents

Common Mistakes

  • Confusing WHO standards with CDC charts — the WHO standards describe optimal growth, while CDC charts describe actual U.S. growth patterns
  • Panicking over a single measurement — growth trends over time are more important
  • Not using corrected age for premature infants during the first 2 years
  • Comparing breastfed and formula-fed infants directly — breastfed infants may be leaner, which is normal
  • Using this chart for children over 24 months — switch to WHO 0-5 or CDC 2-20 charts

Frequently Asked Questions

What age range does this calculator cover?

This calculator uses WHO growth standards for children from birth to 24 months (2 years). For older children, WHO provides separate growth references.

Should I use my child’s weight in kg or pounds?

You can use either unit. The calculator converts pounds to kilograms automatically. For the most accurate result, use the weight recorded at your pediatrician’s office.

Is a single percentile reading concerning?

Not necessarily. Pediatricians look at growth trends over multiple visits. A child consistently at the 15th percentile who is growing steadily is usually healthy. Sudden drops or jumps across percentile lines may warrant further evaluation.

Are these the same charts my doctor uses?

The WHO growth standards used here are recommended by the CDC for children under 2 years of age in the United States and are used by health professionals worldwide.

Reference: WHO Child Growth Standards. World Health Organization, 2006. https://www.who.int/tools/child-growth-standards

Related Calculators

Related Sites