Window of opportunity

For the episode of Stargate SG-1, see Window of Opportunity (Stargate SG-1). For time-critical applications in computing, see Real-time computing.

Critical windows in emergency medicine

Illustration of a short gamma-ray burst, a transient astronomical event caused by a collapsing star

A window of opportunity, also called a margin of opportunity or critical window, is a period of time during which some action can be taken that will achieve a desired outcome. Once this period is over, or the "window is closed", the specified outcome is no longer possible.