Baby Growth Percentile Calculator
Is your baby growing on track? Calculate weight, length, and head circumference percentiles based on World Health Organization (WHO) standards to monitor your child's development.
Weight Chart
Mass-for-age
Length Chart
Height-for-age
Head Size
Brain growth tracking
WHO Standards
Global benchmarks
What is a Growth Percentile?
A percentile ranks your baby's size compared to 100 other babies of the same age and gender. It’s a tool doctors use to ensure your child is growing at a steady, healthy rate.
It's Not a Grade!
Many parents worry if their child isn't in the "50th percentile." But 50th just means average. A healthy baby can be in the 5th percentile or the 95th percentile. What matters most is the curve—is your baby following their own steady path of growth over time?
Monitor Weight Gain
Ensures your baby is getting enough nutrition.
Track Height Potential
Length/Height is a key indicator of long-term bone health.
Head Circumference
Crucial for the first 2 years to monitor brain development.
Gender Specific
Boys and girls grow at different rates. Our tool uses distinct datasets for high accuracy.
Interactive Charts
Visualize exactly where your baby falls on the curve compared to other children of the same age.
Flexible Units
Enter data in pounds/ounces or kilograms, inches or centimeters. We handle the math.
Why Use Our Calculator?
WHO Gold Standard
We use the World Health Organization standards for children 0-2 years, recommended by the CDC and pediatricians worldwide.
Instant Peace of Mind
Quickly check your baby's measurements between doctor visits without needing a login or app.
Safe & Private
Your child's health data is processed locally on your device. We never store or share your information.
Calculate Your Baby's Percentile
Enter your baby's details below.
Used to calculate exact age in months.
How to Use the Growth Calculator
Get accurate results in 3 steps.
Enter Date of Birth
Growth standards change by the week for newborns. Entering the exact DOB allows us to calculate the precise age in months/weeks for the most accurate percentile.
Input Measurements
Enter weight and length. If you have recent measurements from a pediatrician visit, use those. You can select Metric (kg/cm) or Imperial (lb/in) units.
Analyze Chart
Review your baby's position on the growth curve. Remember, consistency is key—staying on the same curve line is usually a sign of healthy growth.
Decoding the Numbers
What does "75th Percentile" really mean?
High Percentile (75th-95th)
Means your baby weighs more than 75-95% of babies their age. This is usually healthy! It just means they are bigger. However, sudden jumps *across* percentiles should be discussed with a doctor.
Average Range (25th-75th)
The "middle of the pack." Most babies fall here. 50th percentile is the exact median. Being here implies steady, standard growth.
Lower Percentile (< 15th)
Means your baby is smaller than average. This can be perfectly normal (genetics). Doctors only worry if a baby *drops* significant percentiles over time (Failure to Thrive).
How to Measure At Home
Babies are wiggly! Use these tricks to get accurate numbers without professional equipment.
The "Subtraction" Method
Don't try to put the baby on a bathroom scale. Instead:
1. Weigh yourself holding the baby.
2. Weigh yourself alone.
3. Subtract your weight from the total.
(Total - You = Baby)
The "Pencil Mark" Trick
Lay the baby flat on a piece of paper or a sheet.
1. Gently mark where the top of their head is.
2. Gently stretch one leg straight and mark the heel.
3. Move the baby and measure the distance between the marks.
The "Eyebrow" Line
Use a soft, flexible measuring tape (like for sewing). Wrap it around the widest part of the head:
• Just above the eyebrows.
• Above the ears.
• Around the back of the skull.
Average Weight by Age (WHO)
Applications of Tracking
Why parents need this tool.
Doctor Visit Prep
Pediatricians use these charts at every wellness check. Tracking at home helps you understand the doctor's feedback and ask better questions about nutrition and milestones.
Feeding Adjustments
A sudden drop in weight percentile might indicate issues with breastfeeding latch or formula intake. Tracking helps catch these trends early so you can consult a lactation consultant or doctor.
Developmental Milestones
Growth isn't just physical size. Look for these skills at each growth stage.
The Smiler
At this size, your baby starts smiling at people, tries to look at parents, and turns their head towards sounds. They can hold their head up for short periods during tummy time.
The Roller
Babies begin to roll over from tummy to back. They can hold a toy and shake it (and swing at dangling toys). They coo and babble with expression.
The Sitter
Often sits without support. Likes to look at self in mirror. Responds to own name. Begins passing things from one hand to the other. Introduction to solid foods usually begins.
The Cruiser
Pulls up to stand and walks holding onto furniture ("cruising"). May take first steps alone. Says "mama" or "dada". Plays games like peek-a-boo.
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Frequently Asked Questions
Should I worry about a low percentile?
Not necessarily. Some babies are naturally small due to genetics (small parents). The most important factor is that your baby follows their own curve steadily and doesn't drop significantly across multiple percentiles.
WHO vs CDC Standards?
The WHO standards describe optimal growth for healthy, breastfed children and are recommended for ages 0-2. CDC charts describe how children actually grew in the US during a specific time period. We use WHO data.
How often should I measure?
For newborns, weight is often checked weekly. After that, usually at routine 1, 2, 4, 6, 9, and 12-month checkups. Measuring too often at home can cause unnecessary anxiety due to daily fluctuations.
What is "Failure to Thrive"?
This is a medical term for when a child's weight or weight gain is significantly below that of other children of similar age and gender (often below the 3rd or 5th percentile). Consult a doctor if you suspect this.