Live rating

A live rating tries to show what a player's rating would look like if recent results had already been incorporated. This is useful because the International Chess Federation (FIDE) does not publish a new official list after every game: its rating regulations provide for an official list on the first day of each month.

Specialized services such as 2700chess and Chess.com calculate FIDE rating changes as results become available. A player can therefore have one published official rating and a different live figure during an event. The live figure is a projection, not a new official FIDE rating list.

The estimate can change when games have not yet been reported, a result is corrected, a game turns out not to be rating-eligible, or services receive information at different times. It is also different from performance rating, which describes the level represented by a particular performance rather than projecting the player's accumulated rating.