Choosing the right BJJ gi for your size

Why A-sizes aren't standardized

The A-size scale (A0 through A5, with F-sizes cut for women) is the closest thing BJJ has to standard sizing — but it is a convention, not a regulated standard. Each manufacturer publishes its own height-and-weight chart, so an A2 from one brand can run noticeably longer or slimmer than an A2 from another. This is the root of nearly every "it fit my training partner but drowns me" story.

That is exactly why the gi size finder gives you a starting A-size to confirm against the specific brand's chart, rather than pretending one number is universally correct.

Start with height, adjust for build

Height drives the base recommendation more than weight does — sleeve and pant length are the hardest things to fix after purchase. Once you have a starting size, adjust for build: if you're heavier or more muscular for your height, you may size up or look for a brand with a roomier cut; if you're lean, a trimmer-cut gi avoids excess fabric for a grip to exploit.

Don't forget shrinkage

A cotton gi will shrink, and how much depends almost entirely on how you wash it. Hot wash plus hot tumble-dry shrinks the most; cold wash and hang-dry shrinks the least. Pre-shrunk and ripstop fabrics move far less than standard cotton. If a gi sits between two sizes, your laundry habits can be the tiebreaker — plan to size slightly up and wash warm, or buy true-to-size and wash cold. The gi shrinkage calculator estimates the direction and rough magnitude for your fabric and routine.

Where to buy

Once you know your size and the brand's chart confirms it, you've removed the main reason gis get returned. A few brands with consistent, well-documented sizing are good places to start.

The bottom line

Use a starting size, confirm it against the actual brand chart, account for how you'll wash it, and prioritize getting sleeve and pant length right. Do that and ordering a gi online stops being a gamble.