Unix Timestamp Converter
Convert Unix timestamps using explicit seconds or milliseconds, and debug dates that appear in the wrong year.
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Practical guide
Check seconds versus milliseconds
Unix timestamps are commonly stored in either unit. If a conversion lands in an implausible year, select the other unit instead of relying on the number of digits.
Read timestamp results in UTC
Both 1609459200 seconds and 1609459200000 milliseconds produce 2021-01-01T00:00:00.000Z. The trailing Z means UTC.
Convert dates from browser local time
The Date to Timestamp tab interprets the entered wall-clock time in your browser’s local timezone. The same typed date and time can therefore produce different timestamps in different timezones.
How to use
For Timestamp to Date, enter a whole number and select Seconds or Milliseconds; the result is ISO 8601 in UTC. For Date to Timestamp, enter a date and time interpreted in your browser’s local timezone, then select the output unit.
Example
Limitations
Timestamp inputs must be whole numbers within the supported date range. Timestamp-to-date output uses ISO UTC. Date-to-timestamp input uses your browser’s local timezone; daylight-saving transitions may make a local time ambiguous or unavailable.
Frequently Asked Questions
Why does my timestamp show the wrong year?
A seconds value interpreted as milliseconds, or the reverse, can produce an unexpected year. Select the unit used by your source.
Does it support milliseconds?
Yes. Select Milliseconds explicitly; the tool does not guess the unit from the number of digits.
Can I convert timestamps before 1970?
Yes, when the date is within the browser-supported range. For example, -1 seconds is 1969-12-31T23:59:59.000Z.
Are entered dates treated as UTC?
No. Timestamp results are displayed in UTC, but a date entered in Date to Timestamp is interpreted in your browser’s local timezone.