Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates in either direction, with automatic seconds/milliseconds detection, relative time, and batch conversion.
Timestamp → Date
Date → Timestamp
Batch Convert
How to Convert a Unix Timestamp
- Check the live "Current Unix Time" counter at the top, which updates every second.
- To convert a single timestamp, enter the number in the Unix Timestamp field. Leave the unit on Auto-detect and it will tell seconds from milliseconds by counting digits, or pick a unit manually.
- Read the result in four formats — local time, UTC, ISO 8601, and RFC 2822 — plus a relative time like "3 hours ago" or "in 2 days".
- To convert many timestamps at once, paste one per line into the Batch Convert box; each line is auto-detected and converted independently.
- To go the other direction, pick a date and time in the Date → Timestamp field to see its seconds and milliseconds values.
Frequently Asked Questions
What is a Unix timestamp?
A Unix timestamp (or epoch time) is the number of seconds that have elapsed since midnight UTC on January 1, 1970 — it's how most databases, APIs, and programming languages store dates internally.
What's the difference between seconds and milliseconds mode?
Some systems, like Unix/Linux and most APIs, store timestamps in seconds, while JavaScript's Date object and some web systems use milliseconds. The Auto-detect option figures out which one you mean by counting digits — 10 digits or fewer is treated as seconds and 11 or more digits is treated as milliseconds — or you can force Seconds or Milliseconds manually from the dropdown.
Why does the tool show four different date formats?
Local time reflects your device's time zone setting, UTC shows the same instant with no time zone offset, ISO 8601 shows the standardized machine-readable format used in code and APIs, and RFC 2822 shows the format used in email headers and HTTP dates.
What happens if I enter a timestamp that's invalid or too large?
The tool displays an invalid timestamp message if the number can't be parsed into a valid date, since JavaScript's Date object has range limits far beyond any realistic date.
Does the Date to Timestamp conversion use my local time zone?
Yes — the date and time input reflects your browser's local time zone, so the timestamp it produces corresponds to that local moment, not UTC.
What does the relative time (for example, 3 hours ago) mean?
It's the difference between the converted timestamp and the current moment, shown in the largest whole unit that fits (seconds, minutes, hours, days, months, or years), with the word ago for timestamps in the past and in for timestamps in the future.
Can I convert multiple timestamps at once?
Yes — the Batch Convert box accepts one timestamp per line, auto-detects seconds or milliseconds for each line independently by counting digits, and returns the UTC time and ISO 8601 date for every valid line, skipping any line that isn't a valid number.