A runtime error is a program error that occurs during the execution of the computer program, i.e. during runtime, and is not detected during program development. The term runtime error deliberately distinguishes itself from other program errors or bugs, such as syntax error or compile time error.
There are the most different kinds of runtime errors. These include logical errors that produce incorrect output, such as those that occur when calculation errors occur in the source code or in a spreadsheet and produce incorrect results, or memory leaks that result in higher memory usage.
Runtime errors can cause the program to crash, causing the program to stop working unexpectedly. Such crashes can be caused by memory leaks or other program errors. Typical examples of faulty programs include division by zero, calling invalid functions, or incorrect use of input. Runtime errors can be limited by testing in advance of deployment.