Timestamp converter
Convert integer Unix timestamps and known-offset dates, with UTC and IANA-zone display.
- 1Add input
- 2Adjust settings
- 3Get your result
Tool input and files are processed in this browser without being uploaded.
Before you start
Convert integer Unix timestamps and known-offset dates, with UTC and IANA-zone display.
How to use this tool
- Choose Unix timestamp or ISO date with timezone before entering a value.
- For a Unix timestamp, select seconds or milliseconds; choose an IANA display time zone, then convert.
- Review UTC and local results. Copy an individual value or download the full result.
Supported inputs and limits
Primary text allows 1 MiB UTF-8. Unix values must be integer seconds or milliseconds with an explicit unit; decimal .00, exponents and fractional Unix values are unsupported.
UTC and displayed local dates both require Gregorian years 0001–9999. UTC milliseconds range from −62135596800000 to 253402300799999, retaining millisecond precision and exact decimal seconds.
Use YYYY-MM-DDTHH:mm with optional seconds and up to three fractional second digits, followed by Z or a known ±HH:mm offset. −00:00, leap seconds and offset-free dates are unsupported. Display zones require runtime IANA names or UTC; local, system, UTC+3 and +03:00 display parameters are unsupported.
The display-zone parameter allows 100 UTF-8 bytes and all active parameter values together allow 2 MiB. Calculation stops after 10 seconds; failure or cancellation produces no partial result. Adjust the input and retry.
Worked example
Example input
0
Example options
{}Example output
{
"milliseconds": "0",
"seconds": "0",
"iso": "1970-01-01T00:00:00.000Z",
"zone": "UTC",
"local": "1970-01-01T00:00:00.000"
}When something does not work
Check the integer unit, valid calendar date and known offset, choose a supported IANA display zone, and keep UTC and local dates in years 0001–9999. Retry from the same input after cancellation or timeout.
Frequently asked questions
How should I hand off a repeated local time?
Two distinct UTC instants can display the same local time. Hand off the full UTC/epoch and zone result; a local display label alone does not identify an instant.
Why is −00:00 unsupported?
It means the UTC instant is known while the local offset is unknown. This tool requires a known offset; determine the source offset rather than guessing a local zone.
Is input uploaded?
Calculation stays in the browser while ordinary site resources still load. Download results you need to keep.
Documentation & further reading
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