How to Wash a Gi (and Keep It From Shrinking)

Most gi care mistakes happen in the dryer, not the wash. The cotton in a jiu-jitsu gi is pre-shrunk to a point, but it still reacts to heat. A wash at 40°C with a tumble dry session is enough to drop a gi one full size. The wash cycle, with the right temperature, is almost entirely safe. The dryer is not.

Quick answer: Wash your gi inside out in cold water (30°C or lower) on a gentle cycle with a small amount of mild detergent and no fabric softener. Skip the dryer entirely. Hang it in a shaded, well-ventilated space and let it air dry completely before storing or training again.

Jiu-Jitsu Gear

Water Temperature: The Variable That Matters Most

Cotton shrinks because heat breaks the tension locked in the weave during manufacturing. Below 30°C, that process barely happens. Above 40°C, it accelerates noticeably. Above 60°C, a gi can lose a full size in one wash.

Cold water also does a better job on the organic material in sweat. Hot water sets protein-based stains rather than lifting them. For a gi that's been used in training, cold water cleans more effectively than warm on the things that matter: sweat, bacteria, and odor compounds.

When to Use Warmer Water

There are two scenarios where going up to 40°C is justified: a gi that has visible mold (usually from being left wet in a bag for more than 24 hours), or a heavily stained gi that has not responded to cold washing. In those cases, 40°C is the ceiling. Anything higher is a gamble on fit that's hard to reverse.

How to Wash a Gi: Step by Step

The process itself isn't complicated. What matters is which decisions you make at each step.

1. Turn the gi inside out. This protects the outer weave from friction in the drum and reduces color fading on darker gis. It also means the inner surface, which holds more sweat and bacteria, gets more direct contact with the water and detergent.
2. Use a small amount of mild detergent. About half the recommended dose is enough. Excess detergent leaves residue in the cotton that traps bacteria over time and makes the gi stiffer after repeated washes. Avoid enzyme-based detergents if you train in a gi with embroidery, since enzymes break down protein fibers and can degrade the thread.
3. Set the machine to cold (30°C maximum) and gentle cycle. A high-speed spin cycle creates mechanical stress on the weave. A gentle cycle at low RPM protects the stitching at stress points: collar, cuffs, and lapels.
4. Skip fabric softener. Fabric softener coats cotton fibers with a thin film that reduces water absorption and traps odor over time. A gi that starts smelling quickly despite regular washing often has softener buildup. If you want to reduce static or make the gi feel softer, a splash of white vinegar in the softener compartment does the same job without the residue.
5. Never use chlorine bleach on a colored gi. On a white gi, diluted oxygen bleach can be used occasionally to brighten the fabric, but chlorine bleach degrades cotton fibers with each use and should be avoided entirely.

The Dryer Question

The answer is no. Even a brief tumble dry session introduces heat that the cotton in a gi cannot safely absorb without shrinking. The foam in the lapels is also compressed under heat in a way that doesn't recover fully, changing how the gi sits and how durable the collar is under grip pressure.

Some practitioners use the dryer on the lowest heat setting or for a short cycle to reduce drying time, then air dry the rest. If you do this, keep the cycle under 15 minutes and check the gi immediately when the cycle ends. The risk is still real. If you have a backup gi, the safest choice is to always air dry and plan washes so the gi has time to dry before your next session.

How to Air Dry a Gi Correctly

Hang the jacket by the collar on a wide hanger or over a rack with the arms out. Don't fold it over a rod since that creates a crease across the back that sets as the cotton dries. Hang the pants by the waistband. Both pieces should be in a shaded, ventilated space. Direct sunlight bleaches colored gis and can yellow white ones over time.

A gi that doesn't dry fully before training again carries bacteria from the incomplete drying process into the next session. If you train the next morning, wash the gi immediately after training, not later that evening.

Washing a White Gi vs. Colored Gi: What's Different

White gis allow for more aggressive cleaning methods because color fading isn't a concern. Colored gis need softer detergents and lower temperatures to hold the dye.

For white gis, baking soda is effective on sweat stains and general yellowing. Add 125g directly to the drum (not the detergent drawer) with your normal detergent. White vinegar in the softener compartment neutralizes odors and brightens the fabric without damaging fibers. For persistent staining, an oxygen bleach soak (30 minutes in cold water, before the wash) is more effective than running the gi through at a higher temperature.

For colored gis, turn them inside out every wash, use a detergent marked as color-safe, and avoid any brightening agents. Wrist and collar areas, where sweat concentration is highest, may still discolor over time. That's normal wear. Soaking in cold water with baking soda before washing slows the process but doesn't stop it completely.

If you also train no-gi and use rash guards, those follow different care rules: machine wash cold, inside out, never the dryer, but they dry much faster than a gi and can go in the same wash.

What to Do About a Smelly Gi

A gi that smells after washing has bacteria embedded in the cotton fibers, not surface dirt. Regular detergent washes the surface but doesn't reliably reach bacteria lodged inside the weave.

The fix: one wash cycle with 125ml of white vinegar instead of detergent, cold water, gentle cycle. The acidity disrupts the bacterial environment. Dry completely before the next wash. If the smell returns after one session, repeat the vinegar cycle once more before adding detergent back. Don't combine vinegar and detergent in the same wash; they neutralize each other.

The root cause is almost always leaving the gi in a bag for more than a few hours after training. Wet cotton in an enclosed space is ideal for bacterial growth. The vinegar cycle treats the problem. Getting the gi out of the bag and onto a rack immediately after training prevents it from coming back.

How Often to Wash Your Gi

After every training session. There is no case for skipping a wash after contact training. Sweat and bacteria begin degrading cotton fibers from inside the weave, and the smell issue is exponentially worse if you train twice on the same unwashed gi.

A jiu-jitsu gi that's washed after every session and air dried will last three to five years with regular use. One that's washed inconsistently or occasionally dried in the dryer will lose fit and structural integrity much sooner.

Gi care is one of those habits that takes about 30 seconds of decision-making per wash and pays off over years of training. The decisions that matter are cold water, no dryer, and wash immediately after training. Everything else is optimization.