Gi sizing confuses people because it isn't clothing sizing. There's no small-medium-large — it's A0 through A4, driven mostly by your height, and it behaves differently from anything else in your wardrobe.
Here's how to get it right, including one thing most brands won't tell you about their own gear.
Start here: our sizing runs small
We'd rather say it plainly than have you post a gi back.
Order one size up from what you'd normally wear.
For a concrete example — our own founder takes an XL t-shirt in everyday clothes, and wears a 2XL rash guard, 2XL shorts and an A4 gi. That's not a one-off; it's how the gear is cut. Our gis are cut to IBJJF competition measurements — sleeves to the wrist, pants to the ankle — which is about passing a uniform check rather than about being slim. What matters for ordering is simpler: the sizing runs small next to streetwear, and cotton shrinks a little on top of that.
If you're between two sizes, go up. If you're comparing to a t-shirt, go up. The only people who shouldn't size up are those already at the top of a size's height range.
Adult gi sizing
Height matters more than weight. A tall, light person needs the length. A shorter, heavier person should follow their height rather than their weight — the gi sits a little looser through the body, which is fine, where a sleeve that is too short is not.
| Size | Height | Weight |
|---|---|---|
| A0 | 150–160cm | 45–60kg |
| A1 | 160–170cm | 60–70kg |
| A2 | 170–180cm | 70–85kg |
| A3 | 180–190cm | 85–100kg |
| A4 | 190cm+ | 100kg+ |
Sitting between two rows, or right on a boundary? Take the larger one.
Shrinkage: plan for it
Cotton shrinks. Pearl weave and ripstop both settle after the first couple of washes, and that's normal rather than a fault — it's the main reason sizing up is the safer error.
You can keep shrinkage to a minimum by washing cold and hanging it to dry, never tumble drying. A single hot wash can take an A2 to something closer to an A1, and there's no way back from that. We've written the full gi care guide if you want the detail.
A gi that feels very slightly roomy on day one is a gi that fits properly in a month.
Kids sizing
Kids gis run M000 to M4, on height with age as a rough cross-check. Children being children, use the height.
| Size | Height | Age guide |
|---|---|---|
| M000 | under 105cm | 3–4 |
| M00 | 105–115cm | 4–5 |
| M0 | 115–125cm | 5–7 |
| M1 | 125–135cm | 7–9 |
| M2 | 135–145cm | 9–11 |
| M3 | 145–155cm | 11–13 |
| M4 | 155–165cm | 13+ |
Sizing up matters even more here, for the obvious reason. A gi with sleeves an inch long gets grown into within a term. One that's snug in March is unusable by June.
Rash guards and shorts
Same rule, and it bites hardest here — compression gear is cut tight by design, so the gap between your t-shirt size and your rash guard size is the widest of anything we sell.
| Size | Chest | Waist |
|---|---|---|
| S | 86–94cm | 71–79cm |
| M | 94–102cm | 79–87cm |
| L | 102–110cm | 87–95cm |
| XL | 110–118cm | 95–103cm |
| XXL | 118–126cm | 103–111cm |
Measure your chest rather than guessing from your t-shirt size. If the tape puts you near the top of a row, take the next one up.
Belt sizing
Belts go by length, and the target is set by the rules: wrapped twice around your waist, double-knotted, with each end hanging 20–30cm.
| Size | Length | Guide |
|---|---|---|
| A1 | 260cm | up to 70kg |
| A2 | 280cm | 70–85kg |
| A3 | 300cm | 85–100kg |
| A4 | 320cm | 100kg+ |
A belt that's too long is a nuisance and technically outside the competition spec. Too short and it won't hold your jacket closed. This is the one item where sizing up isn't automatically right — match it to the guide.
Still not sure?
Tell us your height, weight and usual t-shirt size and we'll tell you what to order — we'd much rather answer a message than process a return. And if it does land wrong, you have 30 days.