Growth Chart Calculator
WHO and CDC references
At age 6, the CDC median weight is about 20.5 kg for boys and 20.2 kg for girls. Use the calculator below to check weight percentile first, then compare that result with height and BMI because school-age growth is best read as a full pattern rather than a single scale number.
This embedded tool follows the same setup as the growth chart calculator. Weight percentile is highlighted first, while height and BMI stay visible so one number is not read in isolation.
Percentile results
Current percentile summary
Interactive charts
Visualize the current percentile position
At age 6, many boys are settling into a steadier school-age growth rhythm. A child can still be completely healthy above or below the median if weight, height, activity, and appetite all fit the same broader pattern. It helps to compare the result with average height and weight by age. The median CDC reference point is 20.5 kg (45.2 lbs), but a healthy child can still sit above or below that midpoint if the broader pattern remains steady.
A 6 year old girl can also follow a healthy curve across a broad range of percentiles. Rather than chasing one average, it is more useful to compare weight with height and BMI and then watch the direction of the curve over repeated visits. The median CDC reference point is 20.2 kg (44.5 lbs), and the trend over repeated visits still matters more than matching the exact median.
Use the unit switch to compare kilograms with pounds across the same percentile rows. The table is meant for quick reference, while the calculator above uses the exact age setup needed for a more precise read.
Boys and girls reference rows with percentile cut points.
| Percentile | Boys (kg) | Girls (kg) |
|---|---|---|
| P3 | 16.2 | 15.7 |
| P10 | 17.6 | 17.0 |
| P25 | 19.0 | 18.4 |
| P50 | 20.5 | 20.2 |
| P75 | 22.4 | 22.3 |
| P90 | 24.6 | 25.0 |
| P97 | 27.9 | 29.0 |
At age 6, the strongest predictor is still genetics, especially parent body build and frame. Diet pattern starts to shift more once school routines and peer influence enter the picture, while recess, sports, and after-school movement can change daily energy balance. Sleep matters too, and most 6 year olds still need about 9 to 12 hours each night. If you want better screening context than weight alone, pair the result with a BMI percentile calculator.
Starting school is a key window for building healthier routines. School lunch patterns, snack choices, and activity after class begin to shape long-term weight trajectory more than they did in preschool. The World Health Organization recommends at least 60 minutes of moderate-to-vigorous physical activity per day for children this age. For age-to-age comparison, you can also review average weight for a 5 year old and the next benchmark for average weight for a 7 year old.
It is worth checking in when weight crosses major percentile channels, BMI rises above usual screening bands, or changes in appetite, fatigue, constipation, chronic illness, or exercise tolerance show up at the same time. This page gives growth-chart context only. If you are worried that a 6 year old may be overweight or underweight, BMI-for-age usually gives a better school-age read than weight alone.
Medical disclaimer
Growth chart results are educational and depend on age, sex, measurement quality, and CDC reference logic. Ask a pediatric clinician about persistent percentile shifts, feeding concerns, puberty-related changes, or any question about weight that does not fit the overall clinical picture.
These answers cover the average weight for a 6 year old, boys versus girls comparisons, pounds conversions, and how weight should be interpreted after starting school.
At age 6, the CDC median weight for boys is about 20.5 kg, or about 45.2 lb. The normal reference range from the 3rd to the 97th percentile is about 16.2 to 27.9 kg. A healthy boy can still fall above or below that midpoint if the overall growth pattern remains steady.
Editorial Review
Content is maintained by our editorial team and reviewed against primary WHO and CDC growth references. Last reviewed site-wide on March 18, 2026.