What is the diameter of the Olympic shot-put circle?

The Olympic shot-put circle has a diameter of 2.135 metres.

The circle’s diameter is specified by World Athletics regulations and applies to senior outdoor shot put. Athletes must remain inside the circle during the attempt and leave only after the shot has landed and after exiting through the rear half.

A stop board is fixed at the front of the circle. It helps athletes brace themselves during the glide or rotational technique and also defines the legal front boundary. The shot must land within the marked sector for the throw to count.

The circle is often confused with the discus circle, which is larger at 2.50 m in diameter. Shot-put circles are also sometimes mistaken for the hammer or combined throwing circle, although those events use different equipment and layouts.