Menu

Calculator Diaper sizes Growth guides Our sources About

Little measurements. A bigger picture.

PRIVATE · EXACT-AGE · WHO & CDC

Know how your child is growing—not just their percentile.

See exact-age percentiles, proportional growth and trends over time. No account; measurements stay on this device.

Exact datesWeight-for-length or BMIPrivate history

✓ Grounded in WHO & CDC data

Your child’s measurements

01

Enter weight or length/height. For infants, head circumference is optional.

YOUR GROWTH COMPARISON

Your percentiles will appear here.

Enter at least one measurement, then calculate to see the comparison and chart.

Ready when you are

Weight for age— percentile

Length for age— percentile

Head circumference— percentile

Weight for age

Girls · Birth to 24 months

Same-percentile reference

Your measurements WHO reference percentiles

Add a measurement to see where it sits on the chart.

i

A percentile is a comparison, not a score.

The 50th percentile is the middle of the reference group. Higher or lower doesn’t, on its own, mean healthier. Measurements over time give more context.

Calculate first, then save to track growth.

THEIR STORY, OVER TIME

Measurement history

Saved locally in this browser. Print or export a readable summary, or make a backup before clearing browser data or changing devices.

Restore backup

Your first saved measurement is the beginning of their growth story.

USE THE MEASUREMENT

From a number to the next decision.

01 / INFANT PERCENTILES

What your baby’s percentile means

Open the infant guide ↗02 / NEWBORN WEIGHT

Average birth weight and the WHO median

See newborn reference values ↗03 / DIAPER FIT

Compare diaper sizes across brands

Find matching sizes ↗

A reference tool, not a diagnosis. If you have concerns about your child’s growth, talk with a healthcare professional. This calculator does not adjust for premature birth.

MOST USEFUL CALCULATORS & GUIDES

Start with the question you need answered.

Weight-for-length calculatorInfant weight in proportion to recumbent length.Child BMI percentileCDC BMI-for-age from age 2 through 18.Extended BMI percentileCDC 2022 method for high BMI values.Growth trackerSave and chart dated measurements locally.Print, export and backupKeep a readable or restorable copy.Infant percentile calculatorWeight, length and head circumference by exact age.Diaper size comparisonCompare six manufacturer weight charts.Baby weight percentile guideUnderstand weight-for-age and its limits.Newborn weight referenceWHO birth medians and percentile table.6-month weight referenceWHO values plus exact-date guidance.