Acceptable Response Times

Some user interface events require shorter response delays than others. For example, an application's response to a user's mouse click or key press needs to be much faster than its response to a request to save a file. The table below shows the maximum acceptable response delay for typical interface events.

Table 7.1. Maximum acceptable response times for typical events

UI EventMaximum Acceptable Response Time
Mouse click, pointer movement, window movement or resizing, keypress, button press, drawing gesture, other UI input event involving hand-eye co-ordination0.1 second
Displaying progress indicators, completing ordinary user commands (e.g. closing a window), completing background tasks (e.g. reformatting a table)1.0 second
Displaying a graph or anything else a typical user would expect to take time (e.g. displaying a new list of all a company's financial transactions for an accounting period)10.0 seconds
Accepting and processing all user input to any task10.0 seconds

Make each response delay in your application as short as possible, unless users need time to see the displayed information before it is erased. The acceptable response delay for each event is based on a typical user's sense that the event is a logical point at which to stop or pause. The greater that sense is, the more willingly the user will wait for a response. Verify that your application responds to users' requests within the limits listed in the table above. If your application cannot respond within those limits, it probably has one or more general problems caused by a particular algorithm or module.

Guidelines