Epoch Auto-Detector

Paste a mystery number and find out what timestamp it is. Detects Unix seconds, milliseconds, microseconds and nanoseconds, .NET ticks, Windows FILETIME / LDAP timestamps, Excel serial dates, NTP, GPS, Classic Mac and Apple Cocoa epochs — ranked by how plausible each interpretation is.

Current Unix time:

Decode a timestamp

Numeric timestamp (decimal or 0x hex)

Try:

Encode a date

Date & time

Time zone of the date above

Large integers (.NET ticks, FILETIME, nanoseconds) exceed JavaScript’s 2⁵³ safe-integer limit, so this page does the math with BigInt — no precision loss. GPS conversion subtracts the current 18 leap seconds. Excel serials before 61 (1900-03-01) are off by one day because of Excel’s fictional 1900 leap day.

Common epochs at a glance: Unix (1970-01-01), NTP (1900-01-01), Classic Mac (1904-01-01), Windows FILETIME and .NET ticks (1601-01-01 and 0001-01-01, in 100 ns units), GPS (1980-01-06), Apple Cocoa / Core Data (2001-01-01), Excel serial dates (days since 1899-12-30).