What are the hammer, the circle and the cage?
Officials' detail · The throw · 2 of 3The men's hammer weighs 7.26 kg and the women's 4 kg, counting the head, wire and handle together. It may be no longer than about 1.2 m. The circle is 2.135 m across inside. Every throw is made from a cage of netting at least 7 m high, with a movable gate that is closed on the thrower's dangerous side.
How it works
| Category | Weight | Greatest length | Diameter of the head |
|---|---|---|---|
| Men | 7.260 kg | 1,215 mm | 110 to 130 mm |
| Under-20 men | 6 kg | 1,215 mm | 105 to 125 mm |
| Under-18 men | 5 kg | 1,200 mm | 100 to 120 mm |
| Women, including under-20 | 4 kg | 1,195 mm | 95 to 110 mm |
| Under-18 women | 3 kg | 1,195 mm | 85 to 100 mm |
- Three parts: "a metal head, a wire and a handle". The weight is the total of all three, and the length is measured from the inside of the handle.
- The head: solid iron, brass or a metal no softer than brass. A shell of such metal with a filling is also allowed.
- The wire: one unbroken, straight length of spring steel wire at least 3 mm thick, joined to the head by a swivel.
- The handle: rigid, with no hinged joints, joined to the wire by a loop and not by a swivel.
- The circle: an inside diameter of 2.135 m, give or take 5 mm, with a white rim level with the ground outside. The hammer may be thrown from a discus circle fitted with a ring that reduces it to that size.
- The cage: "All hammer throws shall be made from an enclosure or cage to ensure the safety of spectators, officials and athletes."
- Its shape: a U in plan. The mouth is 6 m wide and 7 m in front of the centre of the circle.
- Its height: the netting is at least 7 m high at the rear, and at least 10 m for the last 2.80 m before the gates.
- The gates: two movable panels 2 m wide and at least 10 m high at the front. Only one is in use at a time: the left-hand panel for throwers who turn anti-clockwise and the right-hand panel for those who turn clockwise.
- Its strength: it should stop a 7.26 kg hammer head moving at up to 32 metres per second.
- Whose hammer: the organisers provide them. The technical delegates may let athletes use their own, or ones from a supplier, if they are World Athletics certified, checked and marked before the competition and made available to every athlete.
- How many: normally no more than two of an athlete's own for an event.
- No changes: "No modification shall be made to any implements during the competition."
Tricky cases
Can an athlete throw their own hammer?
It depends on the competition. The technical delegates may allow it if the implement is World Athletics certified and has been checked and marked beforehand. It then has to be available to all the athletes.
Can another athlete use an implement that someone else brought?
Yes. An athlete's own implement is accepted on the condition that it is made available to all.
Why is one gate of the cage closed and the other open?
The closed gate covers the side towards which a mistimed throw would go. Which side that is depends on the direction the thrower turns.
Does the 7.26 kg include the wire and handle?
Yes. The weight is the total of the head, wire and handle.
Why the rule exists
A throwing result means something only if everyone threw the same thing from the same place, so the rules fix the weight and shape to the millimetre and let only certified implements in. The cage is there because a hammer released a fraction late leaves the circle sideways at speed, towards the track or the stands.
Where it differs
| Where | What changes | Source |
|---|---|---|
| World Athletics rules | As above | TR 32.1 to 32.3; TR 32.6 to 32.8; TR 36.4 to 36.8; TR 37 |
| Training areas | A simpler cage may be used | TR 37.1 |
| A cage shared with the discus | Concentric circles, or two circles 2.37 m apart with the discus circle in front | TR 37.6 |
| Number of own implements | The technical delegates may allow more than two | TR 32.2 |
From the rule book
World Athletics, Competition and Technical Rules, 2026 Edition, Technical Rules 32.1 to 32.3, 32.6 to 32.8, 36.4 to 36.8 and 37, with the figures printed beside them. Checked 14 October 2026. Official document: World Athletics Competition and Technical Rules 2026 (PDF).