The Year 2038 problem (also called Y2038, Epochalypse,[1][2]Y2k38, or Unix Y2K) relates to representing time in many digital systems as the number of seconds passed since 00:00:00 UTC on 1 January 1970 and storing it as a signed 32-bit integer. Such implementations cannot encode times after 03:14:07 UTC on 19 January 2038. Similar to the Y2K problem, the Year 2038 problem is caused by insufficient capacity used to represent time.
The latest time since 1 January 1970 that can be stored using a signed 32-bit integer is 03:14:07 on Tuesday, 19 January 2038 (231-1 = 2,147,483,647 seconds after 1 January 1970).[3]
Programs that attempt to increment the time beyond this date will cause the value to be stored internally as a negative number, which these systems will interpret as having occurred at 20:45:52 on Friday, 13 December 1901 (2,147,483,648 seconds before 1 January 1970) rather than 19 January 2038. This is caused by integer overflow, during which the counter runs out of usable binary digits or bits, and flips the sign bit instead. This reports a maximally negative number, and continues to count up, towards zero, and then up through the positive integers again. Resulting erroneous calculations on such systems are likely to cause problems for users and other reliant parties.
