Baby Clothes Size Guide
Find the right size based on age, weight, and height. Includes a full reference chart and care advice.
If measurements are entered and conflict with the age selected, we recommend the size that gives more room to grow.
Best fit for a 3–6 month old
Based on the age range you selected. If your baby is larger or smaller than average, see the chart below.
Full size reference chart
| Size | Age | Weight (kg) | Height (cm) |
|---|
What this size covers
Buying tips for this age
About this tool
Baby clothing sizes are usually labeled by age, such as 0-3 months or 6-9 months, but babies grow at very different rates. This calculator checks the age you select against typical weight and height ranges for that size, and highlights when your baby's measurements suggest a different size would fit better.
The reference chart uses common industry weight and height bands, similar to what most major brands use as a general guide. Individual brands can still run larger or smaller, so this is a reliable starting point rather than an exact match for every label.
Frequently asked questions
Should I size up if my baby is between two sizes?
Yes, in most cases. Babies grow quickly in the first year, so a slightly bigger size gets more wear than one that is already snug.
Do all brands use the same size chart?
No. Age-based labels like "3-6 months" are a general guide, not a fixed standard, so the same label can fit differently across brands. Checking weight and height against a specific brand's own chart is more reliable for an exact fit.
How often should I check my baby's size?
Roughly every 4 to 6 weeks in the first year, since growth is fastest during this period. Re-checking before a shopping trip is more reliable than assuming last month's size still fits.