Karate Gi Size Chart for Kids: How to Choose the Right Youth Size

Youth karate gi sizing is set by a child’s barefoot standing height, not age — and the exact manufacturer’s chart for that model always overrules the number on the label.

A gi that fits at the shoulders but pools at the ankles turns every kata into a tripping hazard. Most parents buy by age, the uniform arrives two sizes wrong, and the return window closes before the first class. The fix takes one measurement and one chart check, and it costs about two minutes at the wall.

Below is the height-to-size map most brands roughly follow, the measuring routine that actually works, and the shrinkage math that explains why so many kids start the season in a gi that suddenly hangs too short.

What Do Youth Gi Size Numbers Actually Mean?

The size number on a kids’ karate gi generally tracks the child’s approximate height in centimeters, which is why a “130” tends to suit a child around 130 cm tall. That correspondence is a rough cross-brand habit, not a standard, and labels drift between manufacturers.

A common mapping, gathered from published youth charts, looks like this:

• 0000 or 100 — roughly 95–104 cm, often ages 3–4
• 000 or 110 — roughly 105–114 cm, often ages 4–5
• 00 or 120 — roughly 115–124 cm, often ages 5–7
• 0 or 130 — roughly 125–134 cm, often ages 6–9
• 1 or 140 — roughly 135–144 cm, often ages 7–11
• 2 or 150 — roughly 145–154 cm, often ages 9–13
• 3 or 160 — roughly 155–164 cm, often ages 11–12 or a small adult

Real brands break from this table freely. FUJI’s chart runs sizes 0000 through 7 and asks for age, height, and weight together, with youth bands that don’t line up with the centimeter ranges above. TOKAIDO’s domestic uniforms use their own scale entirely — a size 1 sits at 130 cm, a size 2 at 140 cm — and TOKAIDO’s other lines may measure differently again. Treat any size number as a starting point, never an answer.

How Should You Measure a Child for a Karate Gi?

Measure the child barefoot, standing upright with their back against a wall, from the floor to the crown of the head. That single number drives the whole decision.

1. Have the child stand straight, heels to the wall, shoes off.
2. Run a tape or mark the wall from the floor to the top of the head.
3. Match that height against the specific brand and model’s chart — not a generic one.
4. Check sleeve, trouser, and waist figures wherever the retailer publishes them.

PederKarate, a specialist martial arts supplier, tells buyers outright to measure height without shoes and to use the exact chart for the brand, model, and cut, then confirm trouser waist, sleeve length, and leg length. Those secondary numbers matter most for a child who is unusually slender or broad for their height, where a height-based size can fit the length but swim around the body.

Should You Size Up for Growth or Shrinkage?

A small allowance for growth is standard advice, but the fix for shrinkage depends on the fabric. Several retailers suggest choosing a gi about 5 cm longer than the child’s current height; Decathlon’s Kids’ Karate Uniform 100, sold in 100–150 cm sizes, recommends exactly that and gives the example of a 1.35 m child choosing the 140 cm size.

That guidance assumes a pre-shrunk uniform. Untreated cotton can pull in 3–5 cm after a first hot wash — Hayashi’s sizing notes for its Legend Kids gi flag this directly — so a gi bought with growth room and no shrinkage allowance can end up short after one laundry cycle. Check the care label and the product’s stated shrinkage before you wash.

Balance growth room against safety. A gi several sizes up restricts movement, drags on the floor, and gives an opponent loose fabric to grab. Follow the manufacturer’s guidance when a child lands between sizes; sizing up is the common recommendation, but only within reason.

If you’d rather start from a shortlist than a chart, this roundup of tested youth karate gi options saves a lot of tab-hopping.

How Do You Confirm the Gi Actually Fits?

A correctly fitted gi lets the child move freely in every direction without fabric getting in the way. Check sleeves, trousers, and waistband on the body before the first class, not after.

• Sleeves reach the wrist bone with arms extended straight out.
• Trousers end just above the ankle — no hem under the heel.
• Jacket closes securely across the chest without straining.
• Waistband stays tied and doesn’t dig in.

Then have the child run a stance, a few kicks, a block, and a short kata. If they step on the trouser hem or snag fabric on the way through, the size is wrong regardless of what the chart said. Decathlon’s product guidance and most brand charts agree on the shrink risk over time, so recheck fit after the first wash as well.

Before buying anything, ask the instructor about required color, cut, patches, weight, and competition approval, and whether alterations are allowed. A costume labeled “karate gi” with chest, waist, and hip fields is not the same garment as a dojo-approved training uniform, so confirm the club accepts what you’re ordering. FUJI’s published size chart, Decathlon’s kids’ uniform page, and PederKarate’s sizing guide are the practical references to keep open while you compare.