The CRC Calculator is used to see if the contents of a file have changed. This is particularly useful if you must do something to a file that might accidentally change it, such as storing it on a floppy disk for a long time or sending it over a network or phone line to another computer.

The program computes a CRC (Cyclic Redundancy Check) value for a file. This value depends on the contents of the file, so any changes to the file will change its CRC value.

To use the program, you first compute the CRC value for the file you're interested in, and write it down. Then do whatever you want to do with the file, and compute the CRC value again. If the new value is different than the old one, the file's contents have changed.