Anvil Tools
JWT Decoder
Inspect a JWT header and payload without uploading the token.
Open tool →Unix Timestamp Converter
Convert Unix timestamps to ISO and local dates, or turn a local or UTC date into exact Unix seconds and milliseconds.
Convert Unix time
Compare seconds and milliseconds
Set the source unit before converting. UTC output describes an instant; a timezone-free date entry uses the selected local or UTC interpretation. Local displays depend on the device timezone.
| Input or check | Expected result or decision |
|---|---|
| 0 seconds | 1970-01-01T00:00:00.000Z |
| 1 second or 1000 milliseconds | 1970-01-01T00:00:01.000Z |
| 2026-10-05T12:00 interpreted as UTC | The intended instant is 2026-10-05T12:00:00.000Z; local interpretation may differ. |
| New York DST overlap: 2026-11-01 01:30 | 1793511000 seconds (2026-11-01T05:30:00.000Z, UTC−04:00) or 1793514600 seconds (2026-11-01T06:30:00.000Z, UTC−05:00). The wall-clock time occurs twice. Enter explicit seconds; local displays depend on the device timezone. |
How it works
- Choose seconds or milliseconds when entering a Unix value.
- The result includes UTC ISO time, browser-local time, seconds, and milliseconds.
- When converting a date, explicitly choose whether the entered clock time is local or UTC.
Common uses
- Reading database and API timestamps.
- Creating an exact expiry time for a test.
- Comparing local time with UTC during incident analysis.
Your input stays in this browser. Nothing entered into this tool is sent to the Anvil Tools server.
A practical walkthrough
- Convert Unix timestamp 0 to inspect the epoch, then compare a current timestamp in seconds and milliseconds.
- Look at the UTC result as well as your local time; they represent the same instant with different timezone displays.
- Read the UTC, local, seconds and milliseconds values above. Select and copy the required value manually.
Tips for a reliable result
A seconds-versus-milliseconds mismatch produces a very different date. Check the unit used by the source API before converting.
What to use next
These tools open separately; inputs are not transferred.
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Open tool →How this tool handles your data
Timestamp conversion happens in your browser and is not sent to an Anvil processing server.
Known limitations
Seconds and milliseconds can be confused. Local output depends on the device time zone, and historical or future daylight-saving rules may differ by platform.
Related guide and Lab test
Questions and troubleshooting
What is Unix time?
Unix time counts elapsed seconds from 1970-01-01 00:00:00 UTC. Many JavaScript APIs use milliseconds instead.
How are time zones handled?
A Unix timestamp identifies one instant. The tool shows that instant in UTC and your browser’s local zone. Date input is interpreted according to the option you choose.
When a timestamp shows an unexpected date
Confirm whether the source uses seconds or milliseconds and whether you are reading UTC or local output. The device timezone affects local values. Out-of-range numbers and invalid calendar input need correction before conversion.
Why do UTC and local time show different hours?
They display the same instant using different timezone rules. Share the UTC value or an explicit timezone when communicating timestamps between systems.
Does the tool fix a wrong system clock?
No. Local time displays and comparisons depend on the device and browser. Confirm your device clock and the source timestamp unit when results look unexpected.
Read the practical guide
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