A default condition specifies the state to which a system or program returns when an unspecified condition is the result of an operation, program, or configuration.

Default conditions serve as the baseline for computer operations. Given the multiplicity of variables involved in normal program operations, it is not unusual for a result or condition to occur that was not anticipated by the original programmer. So that operations do not halt, the program moves to a default condition wherein critical components are specified by pre-set values or states.

A typical default can occur when data input exceeds the anticipated operational range. If, for example, a mathematical function programmed to handle input in the range of 0-100 and the input was, instead, 101, an error condition exists. Instead of the program halting, the program may be designed to generate and error message "Input out of range" and then default to the initial input state or prompt (i.e., to start over with a fresh prompt for data).

In networking, there are variations of default conditions termed default routes that direct packets not specified in the routing table to pre-set hosts or networks.

Default conditions also describe the state of a computer hardware configuration before modification by operation. Computer crashes often return the hardware and operating systems to a default condition preset by the manufacturer or system designer.

Default conditions differ from default values that are simply preset (default) variable values substituted for unspecified values.