A timestamp is a sequence of characters, denoting the date or time at which a certain event occurred. A timestamp is the time at which an event is recorded by a computer, not the time of the event itself. In many cases, the difference may be inconsequential: the time at which an event is recorded by a timestamp (e.g., entered into a log file) should be very, very close to the time of the occurrence of the event recorded.

In some cases, a timestamp can be just the numbering of events, the use of a date_time format to store a timestamp is then not mandatory.

This data is usually presented in a consistent format, allowing for easy comparison of two different records and tracking progress over time; the practice of recording timestamps in a consistent manner along with the actual data is called timestamping.

Timestamps are typically used for logging events or in a sequence of events (SOE), in which case each event in the log or SOE is marked with a timestamp. In filesystems, timestamp may mean the stored date/time of creation or modification of a file.

Examples

Examples of timestamps:

• 2005-10-30 T 10:45 UTC
• 2007-11-09 T 11:20 UTC
• Sat Jul 23 02:16:57 2005
• 1256953732
• (1969-07-21 T 02:56 UTC)-1st FootStep on the Moon, "That's one small step for [a] man, one giant leap for mankind"

Standardization

ISO 8601

ISO 8601

ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988...

 standardizes the representation of dates and times. These standard representations are often used to construct timestamp values.

Other meanings

Timestamp can also refer to:

• A time code
  Time code
  A timecode is a sequence of numeric codes generated at regular intervals by a timing system.- Video and film timecode :...
  
   (in networking or video technology)
• Unix time
  Unix time
  Unix time, or POSIX time, is a system for describing instants in time, defined as the number of seconds elapsed since midnight Coordinated Universal Time of Thursday, January 1, 1970 , not counting leap seconds, which are declared by the International Earth Rotation and Reference Systems Service...
  
  , the number of seconds since 00:00:00 UTC on January 1, 1970
• ICMP Timestamp
  ICMP Timestamp
  The Timestamp is an ICMP message which is used for time synchronization. It consists of the originating timestamp.Message Format: * Type must be set to 13.* Code must be set to 0....
  
  
• A digitally signed timestamp
  Trusted timestamping
  Trusted timestamping is the process of securelykeeping track of the creation and modification time of a document. Securityhere means that no one — not even the owner of the document — should be able to change it once it has been recorded provided that the timestamper's integrity is never...
  
   whose signer vouches for the existence of the signed document or content at the time given as part of the digital signature
  Digital signature
  A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, and that it was not altered in transit...
  
  
• The modification or access time of a file
  Computer file
  A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished...
  
   or directory
  Directory (file systems)
  In computing, a folder, directory, catalog, or drawer, is a virtual container originally derived from an earlier Object-oriented programming concept by the same name within a digital file system, in which groups of computer files and other folders can be kept and organized.A typical file system may...
  
   in a computer file system
  File system
  A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...
  
   or database
  Database
  A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...