Average pediatric weight by age (reference)
This reference summarizes approximate median (50th percentile) weights by age band. It is for context only and does not replace an actual, measured weight.
Estimate-only disclaimer
How to use this reference safely
- Use these values only as a rough context check, not for dosing or prescribing.
- Weights vary widely by sex, genetics, nutrition, and health conditions.
- Whenever possible, obtain a measured weight at the visit or from a recent record.
- For growth assessment, use percentile calculators rather than averages.
Values below are rounded to the nearest 0.1 kg and 0.5 lb for readability.
0–12 months
Approximate median (50th percentile) weights from WHO growth standards.
| Age | Approx median weight (kg) | Approx median weight (lb) |
|---|---|---|
| Birth | 3.3 | 7.5 |
| 1 month | 4.3 | 9.5 |
| 2 months | 5.4 | 12.0 |
| 4 months | 6.7 | 15.0 |
| 6 months | 7.6 | 17.0 |
| 9 months | 8.6 | 19.0 |
| 12 months | 9.3 | 20.5 |
1–5 years
Approximate median weights from WHO growth standards (0–5 years).
| Age | Approx median weight (kg) | Approx median weight (lb) |
|---|---|---|
| 1 year | 9.3 | 20.5 |
| 2 years | 11.8 | 26.0 |
| 3 years | 14.1 | 31.0 |
| 4 years | 16.2 | 35.5 |
| 5 years | 18.3 | 40.5 |
6–12 years
Approximate median weights from CDC growth charts (2–20 years).
| Age | Approx median weight (kg) | Approx median weight (lb) |
|---|---|---|
| 6 years | 20.4 | 45.0 |
| 7 years | 22.8 | 50.5 |
| 8 years | 25.5 | 56.0 |
| 9 years | 28.6 | 63.0 |
| 10 years | 32.3 | 71.0 |
| 11 years | 36.4 | 80.0 |
| 12 years | 40.9 | 90.0 |
Teens (13–18 years)
Approximate median weights from CDC growth charts (2–20 years).
| Age | Approx median weight (kg) | Approx median weight (lb) |
|---|---|---|
| 13 years | 45.5 | 100.5 |
| 14 years | 50.0 | 110.0 |
| 15 years | 54.0 | 119.0 |
| 16 years | 57.3 | 126.5 |
| 17 years | 59.8 | 132.0 |
| 18 years | 61.6 | 136.0 |
Use percentiles for real clinical context
Percentiles show where a child falls relative to same-age peers and help track growth trends over time. Pair weight with height and BMI for a fuller picture.
Related tools
Need dosing guidance? Use the medication-specific calculator after confirming a measured weight.
Frequently asked questions
No. Medication dosing should use a measured, recent weight. Age-based averages can be off by a large margin and may lead to under- or overdosing.
These are median (50th percentile) reference values averaged across boys and girls. Many healthy children fall well above or below the median.
WHO standards reflect optimal growth in infants and toddlers. CDC charts are commonly used from age 2–20 years in U.S. clinical practice.
Use corrected (adjusted) age when interpreting growth in preterm infants, typically until 24 months, and rely on clinical guidance for dosing.
Yes. Growth charts are sex-specific. This reference averages both sexes for simplicity, so use percentile tools for more accurate tracking.
Use the most recent weight available, ideally measured at the visit or within the last few days for dosing or clinical decisions.