Free Growth Chart Calculator for Babies - CDC and WHO Percentiles

Enter your baby’s age, sex, and measurements for personalized growth charts and percentile summaries.

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  By: Tali Ditye, Ph.D., Co-founder

  Updated: October 9, 2025

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Monitoring your baby’s growth helps you understand their development compared to international standards. This tool uses WHO (0-24 mo) and CDC (24-36 mo) reference data to show how your baby’s measurements align with expected patterns for their age and sex.

You’ll see percentile ranks, predicted growth over time, and helpful interpretations of what those numbers mean.

Choose to use U.S. (pounds, inches) or metric (kilograms, centimeters) units, enter your child's information, and visualize their growth trajectory.

After checking your baby’s growth, explore our expert guides on the best baby products of the year, from car seats to strollers, feeding essentials, and more!

The Most Comprehensive Baby Growth Chart Calculator

You must enter the child's sex and age, and your email address. And enter at least one input (weight, height, or head circumference) to get results.

You can print, email, or download your personalized report as a PDF to share with caregivers or keep for your records!

Try the Calculator

Scroll up to use our interactive Baby Growth Chart Calculator, a free, easy-to-use baby percentile calculator that compares your child’s height, weight, and head circumference to international WHO and CDC growth chart standards. Instantly see your baby’s growth percentiles by age and sex, predicted growth trajectories, and personalized summaries that help you track your baby’s development with clarity and confidence.

This infant growth chart tool helps parents understand how their child’s size compares to other babies and toddlers worldwide. Choose your preferred measurement system, U.S. Customary (inches and pounds) or Metric (centimeters and kilograms). The tool automatically adjusts calculations and chart labels. Results can be saved as a downloadable PDF or emailed directly for easy record-keeping and sharing with caregivers or pediatricians.

How the Calculator Works

Our baby growth percentile calculator uses the LMS (Lambda-Mu-Sigma) growth modeling approach employed by both the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) to generate accurate growth percentile curves. This statistical model captures how a child’s measurement (X) compares to a reference population, accounting for age, sex, and expected variability.

In simple terms, this baby weight and height percentile calculator estimates how your child’s size compares to other children of the same age and sex. For example, a height in the 75th percentile means your child is taller than about 75% of their peers.

Each growth chart for babies and toddlers (one for weight, one for height, and one for head circumference) is created using standardized LMS parameters (L = skewness, M = median, S = coefficient of variation) from official CDC and WHO datasets.

Percentile lines (e.g., 10th, 50th, 90th) are generated by applying these values to your child’s exact age, then comparing your inputs to the model’s predicted values to produce accurate baby growth chart percentiles.

Choosing Your Measurement Units

You can enter your baby’s information in either U.S. Customary (inches and pounds) or Metric (centimeters and kilograms) units, depending on your preference. This flexibility makes it ideal for parents looking for an accurate baby weight percentile calculator in either system.

• U.S./Customary Mode (Default): Height in inches, weight in pounds, and head circumference in inches, perfect for American growth tracking.
• Metric Mode: Height in centimeters, weight in kilograms, and head circumference in centimeters, ideal for WHO growth reference data.

The calculator automatically converts and processes your inputs to match WHO and CDC reference data, which are stored in metric form. If you select U.S. units, all results, including percentile summaries and chart axes, will appear in inches and pounds for easy interpretation on baby growth charts by age.

Understanding the Results

After entering your child’s details, you’ll see three detailed growth charts for babies and accompanying summaries:

• Height-for-Age Chart: Tracks your child’s height compared to WHO/CDC norms. We use the term “height” instead of “length” for consistency with everyday usage.
• Weight-for-Age Chart: Compares your baby’s body weight to standard age-based expectations and helps you visualize infant weight percentiles.
• Head Circumference-for-Age Chart: A reliable indicator of brain growth and development in infants and toddlers, helping you interpret head circumference percentiles.

Accompanying each graph, you'll receive a summary explaining your baby’s percentile and predicted growth in 3 and 6 months if they stay on the same trajectory.

For example: “Your child is at the 60th percentile, which means their height is greater than about 60% of children their age. This is considered above average. If they continue on this trajectory, their height in 3 months is expected to be around 32.5 inches, and in 6 months around 34.0.”

How to Take Accurate Measurements

Accurate measurements are essential for meaningful growth tracking. Here’s how to measure your baby’s height, weight, and head circumference correctly:

• Height (Length): Lay your baby on a flat, firm surface. Gently straighten their legs and measure from the top of the head to the heel using a measuring tape or infantometer. For toddlers who can stand, measure while standing straight against a wall without shoes.
• Weight: Use a baby scale for accuracy. Remove clothing and diapers for newborns and infants. For older babies, you can weigh yourself holding your child and then subtract your own weight.
• Head Circumference: Wrap a soft measuring tape around the largest part of your baby’s head, just above the eyebrows and ears, and around the back where the head protrudes most.

Repeat measurements twice to ensure accuracy, and always record results in the same unit of measure each time.

How to Interpret Percentiles

Percentiles describe how your baby’s measurements compare to other children of the same age and sex. Here’s how to interpret what each percentile means:

It’s important to remember that growth percentiles are not grades. They indicate position, not health status. What matters most is consistency over time, not the specific percentile number.

Using the Calculator for Premature Babies

If your baby was born prematurely (before 37 weeks of gestation), growth should be tracked using their corrected age rather than their actual chronological age. This ensures your baby’s development is compared to babies who had the same amount of time to grow since their due date.

How to calculate corrected age:

• Determine your baby’s actual age (the time since birth).
• Subtract the number of weeks your baby was early (based on a 40-week full-term pregnancy).
• The result is your baby’s corrected age.

For example, if your baby is 20 weeks old but was born 5 weeks early, their corrected age is 15 weeks. When using the growth chart calculator, enter 15 weeks (3.5 months) as the baby’s age to generate accurate percentile comparisons.

It’s recommended to use corrected age until about 24 months (2 years) of age, at which point most premature infants have caught up with term-born peers in growth and development. After that, you can begin using chronological age for standard growth tracking.

You can also view our detailed premature baby growth chart for additional guidance on interpreting preterm growth patterns.

When to Talk to Your Doctor

Growth charts are powerful tracking tools, but medical professionals are best equipped to interpret patterns. Contact your pediatrician if:

• Your baby’s growth percentile drops or rises sharply across multiple visits.
• There is a significant difference between weight, height, and head circumference percentiles.
• Your baby’s growth slows or accelerates unexpectedly.
• You notice developmental delays or feeding issues.
• Your baby appears consistently underweight or overweight for their age.

Your pediatrician may review feeding patterns, family growth history, or recommend follow-up assessments. Occasional fluctuations are normal, consistent trends are what truly matter.

Advantages of this Tool

• Accurate and Evidence-Based: Uses official WHO and CDC LMS datasets and algorithms for reliable infant and toddler growth percentile charts.
• Flexible: Works for both U.S. and metric units, with automatic chart conversion.
• Predictive: Provides projected measurements for the next 3 and 6 months using standard growth percentile formulas.
• Visual and Intuitive: Interactive charts make baby growth tracking simple and insightful.
• Exportable: Download or email a full PDF baby growth report for your records or to share with your pediatrician.
• Private and Ad-Free: No distracting or spammy pop-up ads, no tracking, just accurate, secure results.

Limitations & Variability

While based on authoritative datasets, all growth models have natural variation. Individual differences are expected and healthy within a wide range. Percentiles are not grades or goals, they simply show relative position within a reference group. Our baby percentile calculator helps you track patterns, not perfection.

The Science Behind Baby Growth Charts

The CDC and WHO have both published standardized baby growth reference charts derived from large international datasets, capturing millions of measurements of healthy infants and toddlers. These data help form the backbone of every growth percentile calculator for babies.

Why We Collect Email Addresses

We ask for your email address before showing results because we do not run ads and rely on community support to grow our platform. Providing your email helps us keep the site free, ad-free, and continually improving.

Frequently Asked Questions (FAQ)

1. What is a baby growth chart?

A baby growth chart is a standardized reference showing typical weight, height, and head size ranges for babies of the same age and sex, based on large population data from the CDC and WHO.

2. What is a normal percentile for my baby?

There’s no “perfect” percentile, anywhere between the 5th and 95th percentile is considered within the normal healthy range.

3. What does it mean if my baby’s percentile changes?

Minor percentile shifts are common. Consistent downward or upward trends should be discussed with your pediatrician.

4. How often should I measure my baby’s growth?

Pediatricians typically measure at every well-baby visit (e.g., 1, 2, 4, 6, 9, 12 months). You can use the calculator in between visits to track trends.

5. Why is head circumference important?

Head growth reflects brain development and overall neurological growth, especially in the first 18 months of life.

6. How accurate is this calculator compared to a doctor’s chart?

Our calculator uses the same WHO and CDC reference datasets as healthcare providers, offering comparable results when measurements are taken correctly.

7. Can I use this calculator for premature babies?

Yes, but you’ll need to use “corrected age” (age since the due date) for the first two years.

8. My baby is above the 90th percentile, should I be concerned?

Not necessarily. Genetics play a large role. If your baby’s growth is consistent and overall development is healthy, higher percentiles are usually normal.

9. What if my baby is below the 10th percentile?

Some healthy babies naturally grow smaller due to genetics. Consistency and developmental progress are more important than the percentile number.

10. What should I do if I think my baby’s growth has slowed?

Recheck your measurements for accuracy, ensure proper nutrition and hydration, and discuss any ongoing concerns with your pediatrician.

Disclaimer

This report is provided for informational and educational purposes only and should not be considered medical advice. You should not rely on this information to diagnose, treat, or manage any medical condition. Always consult with a qualified health care provider for personalized medical advice, diagnosis, and treatment. In case of a medical emergency, call 911 or your local emergency services immediately. The creators of this baby growth calculator assume no liability for any damages or consequences resulting from your use of the tool.

References

Centers for Disease Control and Prevention (CDC). (2024). CDC Growth Chart Data Files. view data at cdc.gov

World Health Organization (WHO). (2006). WHO Child Growth Standards. view standards at who.int

Flegal, K.M., Wei, R., & Ogden, C.L. (2009). Characterizing extreme values of body mass index-for-age by using the 2000 CDC growth charts. American Journal of Clinical Nutrition, 90(5):1314-1320 [reference].

Kuczmarski, R.J. et al. (2002). 2000 CDC Growth Charts: United States. Advance Data from Vital and Health Statistics, 314, 1–27 [reference].

de Onis, M., Garza, C., Victora, C.G., et al. (2004). The WHO Multicentre Growth Reference Study (MGRS): Rationale, Planning, and Implementation. Food and Nutrition Bulletin, 25(1S), S1–S89 [reference].