The complete epoch timestamp converter
A Unix epoch timestamp is the single most common way computers represent a moment in time. It is just an integer: the count of seconds (or milliseconds) that have passed since the Unix epoch, which is precisely midnight UTC on 1 January 1970. Because it carries no timezone and no formatting, the same timestamp means the same instant everywhere on Earth — which is exactly why databases, log files, JWT tokens, APIs and file systems all store time this way. The downside is that 1700000000 is meaningless to a human reading a log. This epoch converter closes that gap: paste the number and instantly read the date; type a date and instantly read the number.
Seconds vs. milliseconds
The biggest source of confusion when you convert epoch values is the unit. Unix time in seconds is a 10-digit number for any date in our era (for example 1700000000 is November 2023). JavaScript's Date.now(), Java's System.currentTimeMillis(), and many event-streaming systems instead use milliseconds, a 13-digit number such as 1700000000000. This tool auto-detects the unit by digit count, but you can force seconds or milliseconds with the radio buttons. To convert manually, multiply seconds by 1000 to get milliseconds, or divide milliseconds by 1000 (and floor) to get seconds.
UTC, local time and ISO 8601
Once a timestamp is decoded, the same instant can be displayed in many ways. UTC (Coordinated Universal Time) is the canonical, offset-free representation and is what you should log and store. Your local time applies your machine's timezone and daylight-saving rules so the value is human-friendly. ISO 8601 (for example 2023-11-14T22:13:20.000Z) is the interoperable string format understood by virtually every language and the one you should put in JSON APIs. This converter shows all three at once so you never have to guess which representation a downstream system expects.
Converting a date back to epoch
The reverse direction matters just as much. When you schedule a job, set a token expiry, or build a database query, you often need the epoch value for a specific calendar date. Enter the date and time in the second tool, choose which timezone that wall-clock time should be interpreted in, and read off the epoch in both seconds and milliseconds. This is especially handy when you have a date in one region (say, "9 AM in New York") and need the absolute timestamp to compare against UTC log entries.
The Year 2038 problem
Historically Unix time was stored in a signed 32-bit integer, which can only represent seconds up to 03:14:07 UTC on 19 January 2038. One second later the counter overflows and wraps to a negative number, which naive systems interpret as a date in 1901. This "Y2038" bug is the spiritual successor to Y2K. Modern platforms store the timestamp in a 64-bit integer, extending the usable range far beyond the lifetime of the universe, but legacy embedded devices and old databases can still be affected — another reason to verify your timestamps with a reliable converter.
Why this converter is private and fast
Every calculation on this page runs locally in your browser using the standard JavaScript Date and Intl.DateTimeFormat APIs, which are backed by the IANA timezone database. No timestamp you paste is ever transmitted to a server, so it is completely safe to convert production log values, confidential audit times, or customer datetimes. There is no signup, no rate limit, and no tracking of the data you enter. Bookmark this page as your go-to unix timestamp converter, and explore the sister cron expression generator and timezone converter for the rest of your time-wrangling needs.