What Is a Unix Timestamp?
A Unix timestamp (or "epoch time") counts the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, ignoring leap seconds. It's widely used in programming and databases as a compact, unambiguous way to store a point in time.
Worked examples
Formula / Calculation Method
How to Use This Tool
- For Timestamp → Date, enter a numeric timestamp and explicitly choose seconds or milliseconds.
- For Date → Timestamp, choose a date, optional time (defaults to midnight), and UTC or your device’s local time zone.
- Compare the UTC, local, and ISO outputs: each represents the same instant.
- Use the live timestamp panel to copy the current time according to your device clock.
Common Use Cases
Seconds, milliseconds, and time zones
A timestamp identifies an instant; the unit determines its scale. This tool does not guess units from the number of digits. For current dates, seconds often have 10 digits and milliseconds 13, but that is only a clue, not a rule. Negative timestamps describe dates before 1970.
Date inputs are different: a date and clock time need a time zone before they identify an instant. Choose UTC for logs defined in UTC, or Local for the zone shown by your device. Local times skipped by a clock change are rejected; repeated times choose the first occurrence and display a note.
Precision and limits
Timestamp inputs support whole seconds or whole milliseconds. Date → Timestamp accepts hours and minutes and sets seconds to zero. The browser’s Date model ignores leap seconds and supports up to 100,000,000 days either side of the epoch; out-of-range values are rejected. The live clock depends on your device clock, not a network time service.
Unix timestamps are not cron expressions, and a timestamp alone does not validate a JWT signature or an API’s expected unit. Check the receiving system’s documentation before copying a value into production.