What does 50th percentile mean?
Your baby's weight is exactly average—50% weigh less, 50% weigh more. Any percentile 5th-95th is normal.
Health Fitness
Baby Weight Percentile Calculator
Calculate baby weight percentile with your details.
Personalized estimate
Use realistic inputs for the most useful results.
What this calculator does
A baby weight percentile calculator compares your infant's weight to standardized growth charts. If your baby is at the 85th percentile, 85% of babies the same age and sex weigh less. WHO charts are used for birth to 24 months, then CDC charts at age 2+.
How it works
The calculator takes age, weight, length, and sex, then plots on standardized growth charts to determine percentile rank.
Formula
Percentile is read from WHO or CDC growth charts by locating age and weight intersection with percentile curves.
Tips for using this calculator
- Use WHO standards for birth to 24 months
- Track weight over multiple visits, not single measurements
- Breastfed infants may grow slower after 3 months—this is normal
- Investigate if baby crosses two major percentile lines
- Discuss concerns with your pediatrician
Frequently asked questions
Should I worry about 10th percentile?
Not necessarily. 5th-95th are normal. Concern arises if dropping significantly from previous percentiles.
Why do WHO and CDC charts differ?
WHO data comes from breastfed populations; CDC reflects mixed-feeding. Use WHO for infants under 24 months.