Timestamp Converter
Timestamp Converter — runs in your browser. Inputs are not stored.
Unix timestamp ↔ date/time
Enter values, then press Calculate.
Uses the browser’s local time zone. Input is not sent to the server.
How to use
- When you open the page, the current time is prefilled in the Unix value and local datetime, as with Now.
- To convert a number from a log, paste it into Unix timestamp and choose seconds (s) or milliseconds (ms).
- Press Timestamp → datetime to update the local datetime field and the summary below (seconds, milliseconds, ISO UTC, local display).
- After picking a time on the calendar, press Datetime → timestamp to fill the Unix value. Seconds or milliseconds follow the unit radio.
- Use Now to load the current time again, and Reset to clear the fields. The time zone is the browser’s local zone.
- When pasting a JWT
expor a log epoch, check the digit count, pick seconds or milliseconds, then convert.
Key concepts
A Unix timestamp is seconds (or milliseconds) since 1970-01-01 00:00:00 UTC. It appears in REST APIs, JWT exp/iat, database epoch columns, and server logs. This tool maps that number to the browser’s local datetime-local input. The result line shows seconds, milliseconds, a UTC ISO string, and a ko-KR local display so you can compare time offsets.
About 10 digits often means seconds and 13 means milliseconds, but there are exceptions, so setting the unit radio yourself is safer. Reading milliseconds as seconds jumps the date into the year 50,000s; reading seconds as milliseconds looks like the 1970s. Daylight saving and time zone follow the OS/browser. Input is not sent to a server.
Example
Enter second-based 1719900000 and press Timestamp → datetime: in Korea you see around 2 July 2024 plus an ISO (UTC) form like 2024-07-02T…Z. Switch the unit to milliseconds and press Now to fill a 13-digit number, then Datetime → timestamp to check the round trip against the seconds field. Mixing 10-digit and 13-digit logs can jump to 1970 or the year 50,000s, so check the digit count first.
Related: Date calculator · D-day calculator · International age calculator
Frequently asked questions
How do I tell Unix timestamp seconds from milliseconds?
About 10 digits usually means seconds and 13 means milliseconds. Exceptions exist, so pick the unit radio yourself.
Is the timestamp converter time zone UTC?
The local datetime field uses the browser time zone. Only the ISO result line is UTC (<code>Z</code>); the local display uses a Korean date format.
How do I convert a Unix timestamp to a date?
Paste the number in the Unix field, choose seconds or milliseconds, then press Timestamp → datetime. The calendar field and the summary below both update.
Does datetime-local include seconds?
The input field is second resolution (<code>step=1</code>). Check milliseconds in the Unix number field and the milliseconds result line.
What if I enter an invalid number?
Empty values, infinity, or an unparseable Date hide the result or leave the previous value unchanged. Enter numbers only.
Is timestamp conversion history stored on a server?
No. Opening the page and the Now button only read the device clock.
Last reviewed: 2026-09-04