Timestamp Converter
Convert Unix time in seconds or milliseconds to and from dates in any time zone, with daylight-saving gaps flagged.
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Timestamp Converter: complete guide
Walk through the steps and examples, or jump straight to the topic you need.
At a glance
- Unit
- You choose Unix seconds or milliseconds yourself when entering a value.
- Reference point
- 0 is January 1, 1970, 00:00:00 UTC.
- Negative values
- Negative values mean times before 1970.
- Time zone
- Choose from 15 places, including UTC and the browser's time zone.
- Daylight saving time
- Calculated with the offset that actually applied at that time.
- Edge cases
- Skipped times and times that occur twice are told apart and reported.
- Range
- Handles up to +/-8,640,000,000,000,000 in milliseconds.
- Where it runs
- Calculation happens in this browser, and your input is not saved.
How to use Timestamp Converter
Choose the reference time zone first
Choose it once at the top and the date input fields and results below are all tied to it. The region's current offset is shown too, so you never wonder which reference you are looking at. If you change the time zone, the existing result is shown again as a date in the new time zone.
Choose a unit and enter a timestamp
Seconds and milliseconds are not guessed automatically; you choose. If the digit count looks inconsistent with the chosen unit, only a note is shown and your value is never changed, which prevents reading a 13-digit number as seconds and getting a nonsense year.
Go the other way: get a timestamp from a date
Enter the year, month, day, hour, minute and second in the right-hand fields and it reads them in the chosen time zone to make a timestamp. For a date that does not exist, such as February 30, or a value out of range, it points out what is wrong. Click 'Use current time' to fill both sides with the current time.
Copy only the format you need
The result shows the date in the chosen time zone and in UTC, ISO 8601, seconds, milliseconds, the day of the week and the relative time from now. Each line has a copy button so you can take just what you need.
What it’s good for
Checking what time a number in a log is
Server logs and databases record time as numbers like 1700000000. Pick seconds as the unit, enter the number, and the tool shows the date in your chosen time zone and in UTC side by side. If the digit count looks inconsistent with the chosen unit, it only shows a note and never changes your value, which prevents the mistake of reading a 13-digit number as seconds and getting a nonsense year.
Never unsure which time zone you are looking at
The same moment falls on different dates in different time zones. Choose the reference time zone once at the top and the date input fields and the results are all tied to it, with that region's current offset shown too. The result shows your chosen time zone, UTC, ISO 8601, seconds and milliseconds together, so you can copy just the format you need.
Worked examples
Viewing a 10-digit number from a log in different time zones
Unit: seconds - 1700000000UTC 2023-11-14 22:13:20 (UTC+00:00)
Seoul 2023-11-15 07:13:20 (UTC+09:00)
New York 2023-11-14 17:13:20 (UTC-05:00)A time that occurs twice when daylight saving ends
New York - 2026-11-01 01:30:00The earlier one, UTC-04:00: 1793511000
The later one, UTC-05:00: 1793514600Easily confused values
Swipe the table sideways to see the rest.
| Input | How it is read | Watch out for |
|---|---|---|
| 1700000000 | In seconds, it is 2023. | In milliseconds, it becomes 1970. Check the digit count. |
| 0 | 1970-01-01 00:00:00 UTC. | In Seoul it is 9 a.m. the same day. |
| -2208988800 | 1900-01-01. | Negative means before 1970 and is not an error. |
When the result isn’t what you expected
The year comes out as 1970
Reading a 13-digit millisecond value as seconds lands near 1970. Reading a 10-digit value as milliseconds does the same. Switch the unit and convert again. If the digit count looks inconsistent, a note also appears under the input field.
It says the time I entered does not exist
On the day daylight saving time starts, the clock jumps forward an hour and the times in between do not exist. The tool moves it to a time that does exist, calculates, and tells you what it changed it to.
The result date is off by a day
Check the reference time zone. The date is read and shown in the time zone chosen at the top. If you need the UTC value, use the UTC line in the result or set the reference time zone to UTC.
It says the value is out of range
The times a browser can handle go up to +/-8,640,000,000,000,000 in milliseconds. Larger values cannot be calculated, and the tool tells you the limit.
Key terms
- Unix timestamp
- The time elapsed since January 1, 1970, 00:00 UTC, counted in seconds or milliseconds.
- Offset
- The time difference from UTC. UTC+09:00 means 9 hours ahead of UTC.
- Daylight saving time
- A system that sets the clock forward an hour in summer. The same region has a different offset depending on the time of year.
- ISO 8601
- The international notation written like 2023-11-14T22:13:20.123Z. The Z at the end means UTC.
Timestamp Converter FAQ
Is it accurate for regions with daylight saving time?
It calculates with the offset that actually applied at that time. If you enter a time that does not exist because the clock jumped forward, it moves to a time that does exist and tells you; if you enter a time that occurs twice because the clock was set back, it shows both candidates.
Can I enter 0 or a negative number?
0 is January 1, 1970, 00:00 UTC, and negative numbers mean times before that. For example, -2208988800 seconds is January 1, 1900.
Is the converted value sent to a server?
No. It uses the time zone data already in your browser, and all calculation happens inside the browser.
Are leap seconds reflected?
No. The standard is that Unix time does not count leap seconds, and this tool follows the same standard.
Korea has no daylight saving time, so why choose a time zone?
Seoul is always UTC+09:00, so the result does not change. The time zone is always shown to make clear which reference was used, and it also makes it easy to switch and compare when reading logs from overseas servers.
Can I enter a value with a decimal point?
No. Only integers are accepted. If you need the part after the decimal point, switch the unit to milliseconds and enter it as an integer.