How to Choose a BJJ Gi: Fit, Weave and GSM, Explained for Beginners

A gi size is two decisions. The number (A0 to A5) comes from your height and weight, and when the two disagree, weight wins. The cut fixes whatever the number gets wrong. If a gi fits you in one direction and not the other, the number was probably right and the cut was wrong.

Here’s what each cut actually changes, measured on our finished A2 gis laid flat:

Read the bold cells and the rule falls out: Long changes length only. Wide changes width only. Fitted takes width away. So sleeves that stop short are a Long problem, not a reason to size up, because the next number up adds chest you didn’t need along with the sleeve you did. A jacket that pulls across the back is a Wide problem, and more length won’t touch it.

The women’s F-series is its own chart, drawn around different proportions rather than scaled down from the unisex one. If the unisex chart has never sat right on you, start there. Every chart, with a calculator, is in the gi size guide.

Here’s how our gis split by cut over the same two months. The plain A-sizes are the biggest single group, and still well under half:

That fourth row is one gi with a different size top and bottom, at the regular price. If your top half and bottom half have never agreed on a size, the mixed-size gi guide covers how to pick the two sizes.

The weave is the pattern the jacket fabric is woven in. It decides how the gi feels in your hands, how hot it runs and how hard it is for someone to get their fingers into the collar.

Pearl vs gold: pearl is lighter and tighter, gold is softer and heavier. Both last. Single vs double: it’s a trade between heat and durability. Double resists grips and outlasts single, and you’ll feel every gram of it by the last round.

Ours is 450 GSM pearl weave, because a lighter weave that survives years of grip fighting beats a heavy jacket you’re cooking in by round three.

GSM is grams per square metre of the jacket fabric. Higher GSM means thicker, tougher, harder to grip, hotter and slower to dry. Rough bands:

• Up to about 450 GSM: light. Cool, dries between sessions, easier on the scale.
• About 500 to 550 GSM: mid-weight.
• Heavier than that: stiff and warm. Tough, and you’ll feel it in summer.

The part people mix up: GSM isn’t how much the gi weighs. It describes the jacket fabric. A whole gi weighs whatever that fabric comes to at your size, plus the trousers, collar and stitching, so an A3 weighs more than an A1 at the same GSM. If you compete, that matters, because every IBJJF weight limit includes the gi (see IBJJF weight classes). Weigh yourself wearing the gi you’ll fight in.

• Fabric: cotton or cotton-like, not so thick it stops a grip.
• Sleeves: within 2 cm of your wrist with your arm held straight out, parallel to the floor.
• Jacket: reaches your thigh.
• Trousers: within 2 cm of your ankle bone.
• Lapel and collar: no thicker than 1.3 cm, no wider than 5 cm.

The sleeve and trouser lines are where fit and legality meet. A gi one cut too short fails them no matter what colour it is. The full checklist is in our IBJJF gi requirements guide.

A pre-shrunk gi should come to you at its size and stay there. Ours are pre-shrunk. Heat is what moves any gi, so wash cold and hang it to dry. Size to the chart for the gi you want now, not for the gi you hope it shrinks into.

1. White, royal blue or black, so it works for a tournament later.
2. Pearl weave, pre-shrunk, light enough to train in every night.
3. Sized by height and weight, cut by build. Then check the sleeves with your arm out.

Starting from zero? The white belt guide covers what else to bring to the first class, and how to check your gi against the competition rules before you need to.

Spend your attention on fit, not fabric. Any decent pre-shrunk pearl weave will last. A gi in the wrong cut annoys you every round for years. Get the number from your height and weight, fix it with the cut, and if your top and bottom disagree, order them in two sizes.