Boys Clothes Size Guide
Find the right size based on age, weight, and height. Includes a full reference chart and buying advice for boys aged 2 to 18.
If measurements conflict with the age selected, we recommend the size that gives more room to grow. Boys' growth spurts vary a lot, so measurements are worth checking even if you know the age.
Best fit for 8 years
Based on the age selected. If your son 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
Boys' clothing sizes shift between a few different systems as they grow: toddler (T) sizes through about age 4 or 5, then regular numbered kids' sizes, and eventually men's sizing in the mid to late teens. This calculator checks the age you select against typical weight and height ranges for that size, and flags it when measurements suggest a different size fits better.
The reference chart uses common industry weight and height bands similar to what most major brands use as a general guide. Individual brands, especially athletic and fast-fashion labels, 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 he is between two sizes?
Yes, in most cases. Growth spurts can happen quickly, so a slightly bigger size gets more wear than one that is already snug.
When do boys typically move into men's sizing?
It varies a lot by individual growth, but many boys start fitting into men's small around size 14 to 16, and most brands treat size 18 as roughly equivalent to a men's small. Checking chest and inseam measurements is more reliable than age alone at this stage.
Do all brands use the same size chart?
No. Numbered sizes like 8 or 10 are a general guide, not a fixed standard, so the same number can fit differently across brands, and athletic wear commonly runs smaller than everyday clothing.