Tool
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates. Live epoch clock auto-updates every second. Paste any 10-digit (seconds) or 13-digit (milliseconds) timestamp and convert to any timezone.
What is a Unix timestamp?
A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, not counting leap seconds. It provides a single, unambiguous integer to represent any moment in time, independent of timezone or locale. Almost every programming language, database, and operating system supports Unix timestamps natively, making them the universal standard for time storage and exchange between systems.
Seconds vs milliseconds: auto-detecting the format
Most Unix timestamps are in seconds — a 10-digit number currently around 1.7 billion. JavaScript's Date.now() and many browser and web APIs return milliseconds instead, producing a 13-digit number. This converter automatically detects the unit from the magnitude of the input value.
- 10-digit number (e.g. 1700000000) → seconds since the Unix epoch
- 13-digit number (e.g. 1700000000000) → milliseconds since the Unix epoch
- To convert seconds to milliseconds: multiply by 1000
- To convert milliseconds to seconds: divide by 1000 (use Math.floor to get an integer)
Why does epoch time start on January 1, 1970?
The date was chosen by the original Unix developers in the early 1970s as a convenient reference point that predates modern computing. Since virtually all useful timestamps are positive integers, arithmetic and comparisons are straightforward. Although the choice was somewhat arbitrary, it became universal — every modern operating system, programming language, and protocol uses the same reference point.
How to convert epoch time to a human-readable date
Use the Epoch → Date tab above: paste any Unix timestamp, choose your timezone, and click Convert. The tool displays the result in ISO 8601 (with timezone offset), UTC string, a friendly long-form format, and a relative time indicator. You can also convert in the opposite direction using the Date → Epoch tab.
- ISO 8601 — standard machine-readable format: 2023-11-15T06:13:20+00:00
- UTC string — human-readable with day-of-week: Wed, 15 Nov 2023 06:13:20 GMT
- Friendly — locale-style: Wednesday, November 15, 2023 at 6:13:20 AM UTC
- Relative — contextual: 1 year ago
Frequently asked questions
- How do I convert a Unix timestamp to a readable date?
- Paste your timestamp in the Epoch → Date tab above and click Convert. The tool auto-detects seconds vs milliseconds and displays the result in ISO 8601, UTC, and a friendly format for any timezone you choose.
- What is the difference between Unix time and UTC?
- Unix time is a count of seconds elapsed since 1970-01-01 00:00:00 UTC. UTC (Coordinated Universal Time) is the time standard that defines that reference point. A Unix timestamp always represents the same UTC moment regardless of your local timezone.
- Can a Unix timestamp be negative?
- Yes. Timestamps before January 1, 1970 00:00:00 UTC are negative. For example, -86400 corresponds to December 31, 1969 00:00:00 UTC.
- What is the Year 2038 problem?
- Legacy systems storing timestamps as 32-bit signed integers will overflow on January 19, 2038 at 03:14:07 UTC (max value: 2,147,483,647). Modern 64-bit systems are not affected.
- How accurate is epoch time?
- Standard Unix time counts SI seconds but does not account for leap seconds, so it can be off by up to a few dozen seconds from precise atomic time. For most applications this difference is irrelevant.