The Baby Weight Percentile Calculator has a growth chart.

This baby weight percentile calculator is designed to help you track your child’s weight growth over time and determine their weight velocity.

If you’re wondering “what percentile is my baby?” this guide will walk you through it step by step.

Understanding Your Baby’s Percentile

According to the World Health Organization (WHO):

“If your child is at the 50th percentile on the weight chart, it means that out of 100 children of the same age, 50 weigh more and 50 weigh less. Similarly, if your child is on the 75th percentile, they weigh more than 75 peers and less than 25.”

To assist with this, our free baby growth chart calculator provides percentile estimates based on WHO growth charts.

Purpose of the Baby Weight Chart

Babies often gain weight rapidly at certain ages, which can make it difficult to track growth accurately. This baby weight percentile calculator estimates the average growth trajectory, helping you understand your child’s progress.

WHO growth chart data is the foundation for this calculator, ensuring results are consistent with international standards.

How to Interpret the Baby Weight Percentile Chart

Doctors use specific guidelines to monitor a child’s weight growth, including:

The percentile line should generally rise as the baby gains weight.
Consult a pediatrician if the percentile line jumps across two ranges (e.g., 70th–75th or 25th–30th).
Seek medical advice if your child’s weight percentile is below the 5th or above the 95th percentile.

Our height and weight percentile calculator also allows you to see where your baby’s weight falls compared to peers of the same age.

CDC Growth Charts

Growth charts graph percentile curves for body measurements such as weight, height, and head circumference in US children. Besides the weight percentile chart, you can also access a detailed height percentile chart using our height percentile calculator.

Since 1977, pediatricians and healthcare professionals have used these charts to monitor children’s growth. The National Center for Health Statistics (NCHS) introduced them as reference charts, and the WHO later adopted them internationally. Our free CDC growth chart calculator helps you quickly determine your child’s weight percentile.

Weight Percentile Charts

Below are tables showing weight percentiles for children aged 0 to 13 weeks.

For Girls:

Weeks	3rd	15th	Median	85th	97th
0	2.5	2.9	3.3	3.9	4.3
1	2.6	3.0	3.5	4.0	4.5
2	2.8	3.2	3.8	4.3	4.9
3	3.1	3.5	4.1	4.7	5.2
4	3.4	3.8	4.4	5.0	5.6
5	3.6	4.1	4.7	5.3	5.9
6	3.8	4.3	4.9	5.6	6.3
7	4.1	4.5	5.2	5.9	6.5
8	4.3	4.7	5.4	6.2	6.8
9	4.4	4.9	5.6	6.4	7.1
10	4.6	5.1	5.8	6.6	7.3
11	4.8	5.3	6.0	6.8	7.5
12	4.9	5.5	6.2	7.0	7.7
13	5.1	5.6	6.4	7.2	7.9

For Boys:

Weeks	3rd	15th	Median	85th	97th
0	2.5	2.9	3.3	3.9	4.3
1	2.6	3.0	3.5	4.0	4.5
2	2.8	3.2	3.8	4.3	4.9
3	3.1	3.5	4.1	4.7	5.2
4	3.4	3.8	4.4	5.0	5.6
5	3.6	4.1	4.7	5.3	5.9
6	3.8	4.3	4.9	5.6	3.6
7	4.1	4.5	5.2	5.9	6.5
8	4.3	4.7	5.4	6.2	6.8
9	4.4	4.9	5.6	6.4	7.1
10	4.6	5.1	5.8	6.6	7.3
11	4.8	5.3	6.0	6.8	7.5
12	4.9	5.5	6.2	7.0	7.7
13	5.1	5.6	6.4	7.2	7.9

The baby weight percentile calculator also uses WHO growth chart data to provide accurate results for your child’s weight progression. You can also try our general percentile calculator to compare any value with a set of data points.

Percentile Graphs

Percentile graphs for children by age are displayed below:

For Baby Boys:

Weight percentile chart for boys

For Baby Girls:

Weight percentile chart for girls

These charts are interpreted and calculated by our free growth percentile calculator. For deeper analysis, you may also visit the WHO site.

How the Baby Weight Percentile Calculator Works

Our free calculator requires the following inputs to determine your baby’s growth percentile:

Inputs:

Select your baby’s gender from the first drop-down menu
Enter the child’s age and weight in the respective fields
Click the calculate button

Outputs:

Determines your child’s growth percentile
Shows whether the percentile is within a normal range
Displays a graphical representation of percentile data

Frequently Asked Questions (FAQ)

Should my child follow the same percentile line?

Yes, ideally your child’s growth should follow a consistent percentile line. If the percentile fluctuates by two or more points, consult a pediatrician.

How do I estimate a child’s weight percentile?

To estimate manually:

Draw a horizontal line at your child’s age
Draw a vertical line at your child’s weight
The intersection point indicates the percentile

Alternatively, you can use our baby weight percentile calculator for instant results.

What do I need to calculate a child’s weight percentile?

Your child’s weight
Your child’s age
WHO growth chart for reference

What is a healthy weight percentile?

A normal percentile lies between the 5th and 85th percentile. Percentiles between 85 and 95 indicate overweight, and medical advice may be needed.

Conclusion

Tracking your child’s weight velocity up to age five is crucial to monitor normal or abnormal growth. This WHO-based weight percentile calculator helps you keep track of daily changes in your baby’s weight accurately.

References

Wikipedia – Growth chart, Quantitative Definitions, Common Variants of Normal Growth: Clinical Significance
Khan Academy – Calculate percentiles, Analyzing a cumulative relative frequency graph: Z-score
Lumen Learning – Physical Growth and Brain Development in Infancy, Overall Physical Growth: Body Proportions