Timestamp
A value that records a date and a time of day together, marking one moment: 2025-03-04T14:30:00Z.
A timestamp without a time zone or offset does not identify a moment, only a clock reading somewhere. Some systems store timestamps as a count of seconds from a fixed starting point, which is exact and unreadable to people.
Where it comes up
- Missing or mixed time zonesTimestamps in one column were recorded in different time zones, or carry no zone at all.
- Date and time split or mergedSome rows keep the date and the time in separate columns and others pack both into one.
- Mixed date formatsOne column holds dates written in several different styles.
See also
- Time zoneA region that keeps the same clock time, described by its offset from Coordinated Universal Time (UTC). A time of day identifies a single moment only once its zone is known.
- ISO 8601The international standard for writing dates and times, year first: 2025-03-04 for the fourth of March 2025.
- Serial dateA date stored as a count of days from a fixed starting date, which is how a spreadsheet keeps dates internally. The number 45000 is a day in March 2023 under the most common starting date.