4-month-old baby weight calculator

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Baby Weight Percentile Calculator – Track Your Child’s Growth with WHO Standards

Monitoring your child’s growth is one of the most important steps in ensuring healthy development. The baby weight percentile calculator helps parents compare their child’s weight to international WHO growth chart standards, offering a clear picture of how they are growing compared to peers of the same age and gender.

This guide covers:




  • What weight percentiles mean for babies

  • How to read and interpret the WHO child growth chart

  • Step-by-step instructions to use the percentile calculator

  • Signs that may require a pediatrician’s attention

What Is a Baby Weight Percentile?

A child weight percentile shows how your child compares to 100 other children in the same age group:




  • 80th percentile → your child is heavier than 80 peers and lighter than 20.

  • 50th percentile → your child is at an average weight for their age.

  • 15th percentile → your child weighs less than most children, but may still be perfectly healthy.

Percentiles are not about “good” or “bad.” Instead, they show your child’s growth pattern over time.

Why Doctors Use Growth Percentile Charts

Doctors rely on WHO child growth charts to evaluate children under 5. These charts track:




  • Weight

  • Height/length

  • Head circumference

  • BMI for children

The real value lies in consistency. If your child follows the same percentile line over time, it usually indicates healthy growth. However, crossing two or more percentile lines (e.g., from the 75th to the 25th percentile) may signal growth concerns and require a pediatric evaluation.




How to Read the WHO Baby Growth Chart

When interpreting the chart, remember:

  1. Growth rate is more important than a single weight measurement.

  2. A steady curve usually indicates healthy development.

  3. Sudden jumps or drops across percentiles may require medical attention.

  4. The WHO growth standards are based on age in months, not weeks.

Children may also go through phases where they gain weight before height, or vice versa. This variation is normal and expected.




How to Use the Baby Weight Percentile Calculator

Using the calculator is simple:

  1. Enter your child’s details

    • Age (in months or years, under 5 years old)

    • Gender (boy or girl)

  2. Input weight

    • Use the built-in weight converter if needed.

  3. View results

    • The calculator instantly shows your child’s percentile compared to WHO data.

Example Case

Yvonne, a mother of two, wanted to check her 5-month-old son Vincent’s growth. At a check-up, the pediatrician recorded:

  • Age: 5 months

  • Weight: 8 kg

  • Gender: Male

The calculator placed Vincent between the 50th and 85th percentiles, confirming healthy progress.

FAQs – Baby Growth Percentiles

1. What does a weight percentile mean?
It shows how your child compares to 100 children of the same age and sex.

2. What information do I need?
Your child’s age, weight, and gender are enough to determine the percentile.

3. Can a low percentile still be healthy?
Yes. Some children are naturally smaller or larger. Consistent growth along the same curve is more important than the number itself.

4. When should I worry?
If your child’s growth suddenly crosses two percentile ranges (up or down), consult a pediatrician.

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