How big is a judo mat?
Officials' detail · Competition, judogi and the mat · 2 of 2The fighting surface is a square contest area between 8 and 10 metres across, with a safety area at least 3 metres wide round it in a contrasting colour. At the Olympic Games and World Championships the contest area is 10 metres square. The mats themselves are called tatami.
How it works
| Part | Size |
|---|---|
| Contest area | 8 m by 8 m at least, 10 m by 10 m at most |
| Safety area | At least 3 m wide |
| Between two contest areas side by side | At least 4 m, which may be shared |
| Contest area at the Olympic Games, World Championships and Masters | 10 m by 10 m, with safety areas of at least 4 m |
| One tatami | 1 m by 2 m, 5 cm thick, of pressed foam |
- The two areas must be of different colours with enough contrast to make the edge obvious. On the IJF tour the colours are yellow and red.
- The tatami must be firm underfoot, absorb the shock of a fall and be neither slippery nor rough. They are laid with no gaps and fixed so they cannot move.
- Decoration, such as the name of the host city, may go only on the safety area.
- A video replay system is compulsory at all IJF events.
Tricky cases
Is the safety area out of bounds?
It depends on the action. A new technique started there does not count, but a throw or ground work begun in the contest area may finish there.
Are all competition mats the same size?
No. The contest area may be anything from 8 to 10 metres square. The biggest events use 10.
Why the rule exists
Athletes are thrown at speed, so the surface has to take a fall and the border has to catch a throw that carries past the edge. The colour contrast is for the referee, who has to judge in an instant where an action began.
Where it differs
| Where | What changes | Source |
|---|---|---|
| IJF events | 8 m to 10 m | SOR 8.7 |
| Olympic Games, World Championships Seniors, Masters | 10 m, with 4 m safety areas | SOR 8.7 |
From the rule book
International Judo Federation Sport and Organisation Rules, Section 8.7, and Refereeing Rules, Article 5. Version of 24 July 2026. Checked 14 October 2026. Official document: IJF Sport and Organisation Rules (PDF).