When this tool helps
- Inspect a timestamp from an API response or log
- Distinguish epoch seconds from JavaScript milliseconds
- Copy an unambiguous UTC or ISO 8601 date
DATE & TIME
Unix Timestamp Converter
Convert Unix seconds or milliseconds to a readable UTC date.
Runs locallyNothing is uploaded
PRACTICAL GUIDE
How to use Unix Timestamp
Last reviewed
Convert an integer Unix timestamp in seconds or milliseconds into ISO 8601 and readable UTC time. Showing both units together helps identify the common 10-digit versus 13-digit timestamp mismatch.
How to use it
- Paste or enter the integer timestamp
- Choose seconds or milliseconds to match the source system
- Read the linked seconds, milliseconds, ISO and UTC forms
- Check the relative-time label as a quick unit sanity check
Converting the Unix epoch
- Input
- 0 seconds
- Result
- 1970-01-01T00:00:00.000Z
Unix timestamps count elapsed time from the epoch in UTC. Millisecond timestamps use the same origin with three additional decimal digits.
Formula: milliseconds = Unix seconds x 1,000; Unix time 0 = 1970-01-01T00:00:00.000Z
Limits and assumptions
- The input must be a whole number in seconds or milliseconds
- Output is shown in UTC rather than an inferred local time zone
- Dates outside the JavaScript Date range cannot be represented
Frequently asked questions
How can I tell seconds from milliseconds?
Current Unix seconds usually contain 10 digits, while current Unix milliseconds usually contain 13. Confirm the source system rather than relying only on length.
Does Unix time include a time zone?
Unix time represents an instant. The readable output here uses UTC to avoid local time-zone ambiguity.
Is the timestamp sent to a server?
No. Parsing and date formatting happen locally in the current browser page.