Quick answer: IBJJF gi rules cover the fabric, color, patch placement, belt, sleeve length, pant length, collar measurements, and general condition of the uniform. The safest competition setup is a clean white, royal blue, or black gi that fits within IBJJF measurements, has legal patches only in approved areas, and is checked against the official event and IBJJF uniform page before you compete.
This guide explains IBJJF gi rules in practical terms for BJJ competitors. It is not the official rule book. Use it as a planning checklist, then confirm the current requirements on the official IBJJF uniform page, the IBJJF rules page, and your event page.
| Gi rule area | Common IBJJF requirement | Beginner mistake to avoid |
|---|---|---|
| Color | White, royal blue, or black; top and pants should match. | Wearing a mixed-color gi or non-approved color. |
| Fabric | Cotton or cotton-like fabric; woven fabric is required for all age divisions. | Using fabric too thick or stiff for legal gripping. |
| Belt | Rank-colored belt, 4 to 5 cm wide, tied with a double knot. | Loose belt, wrong rank color, or incorrect tip color. |
| Sleeves | Sleeves should not end more than 2 cm from the wrist with the arm extended. | Sleeves too short after shrinking. |
| Pants | Pants should not end more than 2 cm above the ankle bone. | Pants that are too short or too tight after washing. |
| Patches | Patches must be in authorized areas and properly sewn. | Unsewn, loose, or unauthorized patches. |
| Condition | Gi should be clean, dry, intact, and not unpleasant smelling. | Arriving with a torn, wet, dirty, or strongly odorous gi. |
IBJJF gi colors
For IBJJF competition, the safest gi colors are white, royal blue, and black. The gi top and pants should be the same approved color. A blue top with black pants, a white top with blue pants, or a collar that is a different color from the rest of the jacket can create inspection problems.
If you are buying a gi specifically for competition, choose a simple approved color before choosing style details. Competition inspectors care about legality, fit, cleanliness, and safety before aesthetics.
Gi material and thickness
The IBJJF uniform page says gis should be made from cotton or cotton-like fabric. The material should not be so thick or hard that it prevents the opponent from gripping it. Woven fabric is mandatory for all age divisions.
That matters because a competition gi is not just clothing. It is part of the gripping environment. A gi that is too rigid, too slick, too thick, or built in a way that interferes with normal grips may fail inspection.
IBJJF gi measurements
Fit is one of the most common reasons a gi becomes risky for competition. A gi can be legal when new and become questionable after repeated hot washes, drying, or shrinking. Before an event, check your gi after it has been washed and dried the way you normally prepare it.
| Measurement | IBJJF-style checkpoint | Practical check |
|---|---|---|
| Jacket length | Gi top should reach the thigh. | Stand naturally and check that the jacket is not cropped too high. |
| Sleeve length | Sleeves should come no more than 2 cm from the wrist with arms extended. | Extend your arm straight and check both sleeves. |
| Pant length | Pants should come no more than 2 cm above the ankle bone. | Check after warmups because pants can ride up. |
| Lapel thickness | Inspection references 1.3 cm lapel thickness. | Use a standard competition gi from a reputable brand. |
| Collar width | Inspection references 5 cm collar width. | Avoid unusual collars unless you know they pass inspection. |
| Sleeve opening | Inspection references 7 cm sleeve opening at full extension. | Do not compete in sleeves that are unusually narrow. |
For general sizing help, use GrapplerHQ’s BJJ gi size chart. For competition legality, use the official IBJJF uniform and event pages as the final source.
Belt rules
The belt should match the athlete’s rank and be durable enough to hold the gi closed. The IBJJF uniform page lists a 4 to 5 cm belt width and says the belt should wrap twice around the waist, be tied in a double knot, and leave each end hanging 20 to 30 cm after the knot.
Do not treat the belt as an afterthought. A belt that is too short, too loose, the wrong color, or tied poorly can create problems at inspection or during the match.
Patch rules
Patches should be properly sewn and placed only in authorized regions. Loose, unsewn, or incorrectly placed patches can be removed by inspectors. Painted gis are generally forbidden unless the paint is part of an academy or sponsor logo in an approved patch region and does not mark the opponent’s gi.
If your academy or sponsor patches are important, check placement before tournament week. Waiting until the event inspection line is a poor time to discover that a patch is in the wrong place.
Can you wear a shirt or pants under the gi?
For male divisions, wearing a shirt under the gi top is prohibited under IBJJF uniform rules. For female divisions, a stretchy or elastic shirt under the gi is mandatory. Pants under gi pants are generally prohibited, with an exception for women using elastic fabric pants that are shorter than the gi pants.
Undergarments are required, and thong-type undergarments are not permitted. These details are easy to miss because they feel separate from technique, but they are part of competition readiness.
What can fail gi inspection?
- Wrong color: non-approved colors or mismatched top and pants.
- Bad fit: sleeves or pants too short after shrinking.
- Unsafe material: fabric too thick, hard, torn, or otherwise abnormal.
- Patch problems: patches in unauthorized areas or not properly sewn.
- Poor condition: wet, dirty, torn, or unpleasant-smelling uniform.
- Wrong under-layer: shirt or pants under the gi when not allowed for the division.
Gi rules, weigh-ins, and weight classes
Gi rules connect directly to weigh-ins. In many gi events, athletes weigh in wearing the gi and belt. That means your uniform affects both legality and the number on the scale. If you are near your limit, test your weight in the actual competition gi before the event.
For division planning, read GrapplerHQ’s BJJ weight classes guide. If you are comparing no-gi requirements, read the IBJJF no-gi rules guide.
Beginner competition checklist
- Choose a white, royal blue, or black gi.
- Wash and dry the gi before checking fit.
- Check sleeve length, pant length, and jacket length.
- Confirm patches are sewn and in approved areas.
- Bring the correct belt and tie it securely.
- Weigh yourself in the actual gi and belt if your event requires gi weigh-ins.
- Bring a backup legal gi if you have one.
Bottom line
IBJJF gi rules are not complicated, but small details can matter on tournament day. Use an approved color, keep the gi clean and intact, check measurements after washing, sew patches properly, and confirm your belt and under-layer requirements. The final source is always the official IBJJF uniform page and your specific event page.
FAQ
What gi colors are legal for IBJJF?
IBJJF competition generally permits white, royal blue, and black gis. The top and pants should be the same approved color.
Can you wear a rash guard under the gi in IBJJF?
In male gi divisions, wearing a shirt under the gi top is prohibited. In female divisions, a stretchy or elastic shirt under the gi is mandatory.
Do IBJJF competitors weigh in with the gi?
In many gi events, athletes weigh in wearing the gi and belt. Check the event page because weigh-in procedures can vary.
Can an old gi fail inspection?
Yes. A gi can fail if it is too short, torn, dirty, wet, unpleasant smelling, or otherwise outside the current uniform requirements.
For a source-led overview of the full rules ecosystem, including official rule book links, uniform checks, divisions, scoring, and legal-technique cautions, see GrapplerHQ’s IBJJF rules hub.
