What Is a Gi BJJ? | Traditional Uniform, Rules & Gi Size Guide

Gi BJJ is the traditional division of Brazilian Jiu-Jitsu where athletes wear a heavy cotton kimono, using fabric grips for control and submissions; the gi must meet IBJJF uniform standards for competition.

Walk into any Brazilian Jiu-Jitsu academy and you will see two groups: one in shorts and rash guards, and another in thick cotton jackets with reinforced pants and a belt. That uniform — the gi (also called a kimono in Portuguese) — defines the original, technical side of the sport. Gi BJJ changes how you grip, move, and submit. It demands more precision, rewards fabric-based techniques, and comes with a strict rulebook for competition. Whether you are buying your first gi, checking an old one for a tournament, or just trying to tell Gi from No-Gi, this guide covers the uniform rules, the right fit, and what the IBJJF actually checks at weigh-ins.

How Is a Gi Different From No-Gi?

The gi is a thick cotton training uniform consisting of a jacket, reinforced pants, and a rank belt. In Gi BJJ, you can grip your opponent’s lapels, sleeves, collar, or pants to control movement, break posture, and set up submissions. No-Gi removes the fabric entirely, so grips shift to the wrists, ankles, neck, and torso. That difference changes the sport’s pace. Gi rounds tend to be slower and more grip-dependent, with a heavier emphasis on lapel chokes, Ezekiel chokes, and guard styles like Spider, Lasso, and Worm. No-Gi is faster and relies more on body locks and wrestling-style takedowns. Both are legitimate divisions, but the gi demands a deeper understanding of fabric leverage and positional patience.

What Are the IBJJF Uniform Rules for a Competition Gi?

The International Brazilian Jiu-Jitsu Federation (IBJJF) enforces a strict set of gi specifications to keep competition fair. The gi must be made of 100% cotton or a cotton-like fabric — no synthetics. The jacket and pants must be the same color, and only white, royal blue, or black are permitted. The fabric cannot be excessively thick or hardened to the point that it blocks an opponent’s grip. Gis with tears, stains, bad odors, or wetness are rejected at inspection. Collar thickness is capped at 1.3 cm, and the jacket length must reach the athlete’s thigh. No metal or plastic is allowed on the pants, including zippers, exposed drawstrings, and buttons.

Gi Measurement Requirements After the 2024 IBJJF World Championships

After the 2024 World Championships, the IBJJF enforced tighter measurement standards to prevent overly tailored gis. Athletes must now pass the IBJJF Gi Checker Tool, which confirms eight manual checks. The table below breaks down each measurement in inches and centimeters.

These rules come directly from the IBJJF uniform regulations. The Gi Checker Tool automates part of the process, but athletes need to verify the eight manual steps themselves before weigh-ins — the tool only covers overall criteria, not every detail.

How to Choose the Right BJJ Gi Size

Most brands use an A0-to-A6 system that combines height and weight rather than small/medium/large. A2 fits most men between 5’8″ and 6’0″ weighing 140–190 lbs. But body shape matters more than a single number. If you are taller than average for your weight, look for an L (long) size. Heavier or wider athletes need an H or HY (husky/heavy) cut. Shorter athletes may fit an S (short) variant. Always check the brand’s specific chart because sizing drifts between manufacturers.

The best way to find your fit is to measure your height, weight, chest, arm length (shoulder to wrist), waist, hips, and inseam. Follow weight first, then height — a gi sized off height alone may be too tight through the shoulders. If your measurements fall between two sizes, go larger. Cotton gis shrink about 3–5% after the first wash, and a slightly large gi can be hot-washed and dried to tighten up. A gi that is too small cannot be reversed and will fail the IBJJF sleeve and pants length checks.

Common Gi Sizing Mistakes That Get Athletes Disqualified

The most common failure at IBJJF inspection is sleeves or pants that hang too long — anything beyond 2 cm from the wrist or ankle bone gets flagged immediately. Sizing based solely on height is another frequent error. A tall, lean person following a height chart may end up with a gi that is baggy and fails sleeve-width checks. Newcomers also often shrink a gi too aggressively in the first wash, making it too short. Wash in cold water and hang dry for the first cycle, then adjust with warm water and a dryer if you need a tighter fit. Synthetic or blended gis are prohibited, so check the fabric tag before buying.

Gi BJJ Actions: What You Can and Cannot Do

Gi BJJ allows you to grip any part of the gi — collar, sleeves, pants, belt — and use those grips to control the opponent’s posture, set up sweeps, or finish submissions. Lapel chokes, bow-and-arrow chokes, and Ezekiel chokes are all gi-specific techniques that have no No-Gi equivalent. The gi also makes guard passes harder because the fabric gives the bottom player more control.

Prohibited actions include grabbing individual fingers to break a grip, using the gi to cover the opponent’s face or obstruct airflow, and any technique that uses the gi to strangle with the fabric wrapped around the neck in a way that bypasses the lapel. Wet, dirty, or torn gis are grounds for disqualification. These IBJJF rules apply to all IBJJF-sanctioned tournaments globally; other organizations like NAGA have their own gi rules that may differ.

Comparison: Gi BJJ vs. No-Gi BJJ at a Glance

Bringing Your Gi to the Gym: What Else You Need

Once you have a gi that fits, you need a way to carry it to the academy. , and stuffing it into a regular gym bag leads to mildew and torn fabric. A dedicated BJJ bag with good ventilation makes more sense — check out the best BJJ bags for gear and training for options that handle the weight and keep your gi dry between sessions. A rash guard worn under the gi reduces chafing, and wrestling shoes are not allowed in Gi BJJ, so no special footwear is needed.