How to choose a judo gi: size, fabric weight and price

A judo uniform, or judogi, is a heavy jacket, trousers and a belt. It is built to be gripped and pulled for a whole session, which is why the fabric is heavier and the jacket reinforced, often with a rice-grain weave. A karate gi is much thinner and will not last long on a judo mat. For a first purchase, three things matter: fabric weight, size and colour. The International Judo Federation (IJF) label only matters for high-level competition.

Fabric weight comes first

Fabric weight, measured in grams per square metre (gsm), tells you how thick the jacket is. The higher it is, the better the jacket stands up to grips and the harder it is for a partner to hold. The trade-off: a heavier, warmer jacket that takes longer to dry.

For reference, in Decathlon's range the entry-level children's gi weighs 190 gsm, the children's judo and aikido gi 350 gsm, the basic adult gi 350 gsm and a reinforced adult gi 550 gsm. Competition judogi start at around 750 gsm.

A light gi is fine for a child starting out: they will outgrow it in one or two seasons, long before it wears out. For an adult beginner, 350 gsm will last a season of regular training. If you do randori (free sparring) two or three times a week, a 500 to 550 gsm jacket wears less quickly at the collar and lapels, where the grips go.

Cotton or a polyester blend

Budget judogi mix cotton and polyester. Decathlon's entry-level children's gi is 35% cotton and 65% recycled polyester, and its 350 gsm adult gi uses the same ratio. A blend dries fast, creases less and costs less.

All-cotton judogi are more comfortable and absorb sweat better, but they can lose a few centimetres in the first washes unless they are pre-shrunk. Check the label before choosing a size, and size up slightly if the gi is not pre-shrunk.

Getting the size right

Judogi sizes are given as your height in centimetres: 100 to 150 cm in Decathlon's children's range and 160 to 200 cm for adults. The manufacturer recommends going at least 5 cm above your height, so a 180 for someone who is 1.74 m (about 5 ft 9). For a child, those 5 cm also leave room to grow.

Brands do not size the same way, with differences of around 5 cm between them, so try the gi on if you can. With your arms stretched out in front, the sleeves should reach your wrists; the jacket should cover your backside; the trousers should stop just above the ankle. A jacket that is too big gets in the way and hands your partner an easy grip. One that is too short comes out of the belt every time you fall.

What competition requires

There is no standard for club training: a clean gi that fits is enough. In competition, uniforms are checked. The IJF rules, used at international events, set precise measurements. The sleeves must cover the whole arm including the wrist bone, and a gauge called a sokuteiki must slide fully into the sleeve. The jacket must cover the buttocks with 5 to 10 cm to spare, and the lapels must overlap by at least 25 cm at belt level. The trouser hem must sit no more than 5 cm from the ankle bone. The belt ends must be 20 to 30 cm long from the knot.

At IJF events, the jacket and trousers each carry a red "IJF Approved" label, checked under a UV lamp, and both must be the same brand. A non-compliant judogi means disqualification from the contest, with no spare uniform provided. The label is only required at some high-level events; most tournaments just check the fit. Before spending, read the rules of the event you are aiming for or ask your national federation.

White or blue

White is judo's standard colour, in training and in competition. Blue is used to tell the two fighters apart. The French federation, for example, requires it at its 2026-2027 national first-division championship: white and blue judogi are compulsory, with the first fighter called wearing white. A beginner only needs a white gi. Blue becomes useful once you enter events that ask for it. The IJF bans reversible judogi, white on one side and blue on the other.

What it costs

Prices on Decathlon Pro's French website in October 2026: 11.99 euros for the entry-level 190 gsm children's gi, 34.99 euros for the 350 gsm adult gi and 49.99 euros for the 550 gsm adult gi. The adult gi comes without a belt. IJF-approved judogi are another price bracket: the Adidas Champion III is listed there at 145.79 euros each for orders of ten or more, a club rate, and costs more at retail. In the United States, USA Judo listed the IJF-approved Mizuno Double Weave at a retail price of 269.95 dollars in August 2026.

Ask your club before buying. Many place group orders at the start of the season, sometimes with the club badge embroidered, and some lend a gi for trial sessions.

Care

Wash your judogi after every session. Decathlon advises cold water for the first few washes, then no more than 30 °C, no fabric softener, and air drying rather than the tumble dryer, which speeds up cotton shrinkage. Take the gi out of your bag as soon as training ends. If you train two or three times a week, owning two judogi means you always have a dry one.