You do not need a tailor to size a jersey. Four measurements, taken on a garment you already like, will get you closer than any size letter. This is the method we use when comparing charts.
1. Chest, measured flat
Lay a jersey flat and button or zip it closed. Measure straight across from armpit to armpit, then double the number. That is the chest circumference the chart is talking about. Do not measure around your body in a thick sweatshirt; measure the garment.
2. Body length
Measure from the highest point of the shoulder to the hem. This is the number that decides whether a jersey looks oversized or cropped. Compare it to a jersey you already wear at the length you like, not to your height.
3. Shoulder width
Measure seam to seam across the back of the shoulders. This matters most for authentic and Elite jerseys, which have a structured shoulder. If your shoulders are wider than the seam measurement, the jersey will pull.
4. Sleeve length
For NFL and MLB jerseys, measure from the shoulder seam to the sleeve hem. NBA jerseys are sleeveless, so skip this step and check the armhole depth instead.
Comparing to the chart
Write the four numbers down and match them to the published chart for the exact version you are buying. If two sizes are close, choose based on how you will wear it: over layers means size up, display means the smaller size hangs cleaner.
What not to do
Do not convert from your T-shirt size. Do not assume a men's size equals a women's size. Do not trust a single “true to size” claim without the chart. Fit reports from other buyers are useful, but they are opinions about a body you cannot see.
Charts change by season and manufacturer. Confirm the version before ordering. Paid links on this site may earn us a commission.