MLB jerseys are sized differently from NFL and NBA product, and the gap between replica and authentic is wider than most buyers expect. This guide covers how each version is cut and how to use the published charts without guessing.
Replica jerseys
Replica is the fan version: lighter fabric, printed or heat-applied details, and a cut built for everyday wear. The letter scale is closer to standard clothing, but it still runs roomier than a T-shirt of the same label. Measure a shirt you like and compare chest width before ordering.
Authentic jerseys
Authentic is cut closer to the on-field spec: heavier double-knit fabric, stitched tackle twill, and a longer body. It runs tighter through the chest and shoulders. If you want to layer it over anything, go up a size; if you are buying it to frame or display, take your normal size.
Why the same letter fits differently across teams
Two jerseys with the same label can differ because of manufacturer, season, and template. Older authentic runs are often cut longer than current ones. This is why we record the source and the season for each chart rather than publishing one universal table.
Women's and youth MLB jerseys
Women's MLB jerseys use their own scale and a shorter body. Youth sizes are age-banded and end before adult sizing starts. If a child is near the top of the youth range, measure chest and length rather than moving straight to adult small.
What to check before you buy
Confirm three things on the listing: the version (replica or authentic), the size scale being used, and the return policy. A jersey that is correct on paper but non-returnable is a worse deal than one that costs a little more with a return window.
Charts and templates change by season and maker. Verify the version and chart on the product page. Paid links on this site may earn us a commission.