Date & Time
Unix Timestamp Converter
Convert Unix seconds, milliseconds, ISO dates, UTC, and local time.
Unix Timestamp Converter tool
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About This Tool
Translate Unix epoch values into readable dates or convert a local date and time back into epoch seconds and milliseconds. This is useful when debugging APIs, logs, databases, analytics events, scheduled jobs, cache headers, webhooks, and JavaScript timestamps where a large integer needs to be mapped to an exact moment. The converter keeps seconds, milliseconds, UTC, local time, and ISO 8601 output together so you can spot unit mistakes quickly.
How To Use It
- Choose timestamp-to-date when you have an epoch number, or date-to-timestamp when you have a readable date and time.
- Select seconds or milliseconds when entering a Unix value so the converter interprets its scale correctly.
- Review the UTC, local, ISO 8601, seconds, and milliseconds representations.
- Copy the format required by your application, API, database, or log workflow.
- When converting a date to a timestamp, remember the entered date and time are interpreted in your browser's local timezone.
Examples
Debug a log value
Paste an epoch value from logs or analytics to translate it into readable UTC and local date/time values.
JavaScript milliseconds
A JavaScript Date timestamp is normally measured in milliseconds, so values are roughly 1,000 times larger than Unix-second timestamps for the same moment.
Create an API timestamp
Enter a date and time, then copy Unix seconds when an API expects a traditional epoch value or milliseconds when a JavaScript-style timestamp is required.
Convert an ISO date to epoch time
Use the date-to-timestamp direction when you know the local calendar date and clock time and need Unix seconds or milliseconds for a request payload.
Catch a 10-digit versus 13-digit mistake
A current-looking 10-digit value is usually seconds, while a current-looking 13-digit value is usually milliseconds. Selecting the wrong unit is the quickest way to land on a wildly incorrect date.
Useful Notes
What the Unix epoch means
Unix time counts elapsed time from 1970-01-01 00:00:00 UTC. A timestamp represents an instant, not a timezone-specific wall-clock label. The same instant can be formatted differently in UTC, your local timezone, or another timezone.
Seconds versus milliseconds
Many backend systems store Unix seconds, while JavaScript commonly uses milliseconds. Choosing the wrong unit can produce a date thousands of years away from the intended value.
Date-to-timestamp uses your local timezone
When you enter a readable date and time, the tool interprets that wall-clock value in your browser's local timezone. The resulting Unix timestamp is the UTC instant corresponding to that local date and time.
UTC and local display
The same timestamp can be displayed differently in local time and UTC because those are two representations of the same instant.
ISO 8601 output
The ISO output ends with Z, which means it is expressed in UTC. It is useful for systems that accept explicit UTC timestamps instead of raw epoch integers.
Negative timestamps
Negative Unix timestamps represent supported dates before the 1970 epoch, although the exact usable range can depend on the browser runtime.
Leap seconds and calendar rules
Typical Unix timestamps count regular elapsed seconds and do not encode leap seconds as separate values. Browser date handling also depends on the runtime's supported date range and timezone data.
FAQ
Is Date to Unix Timestamp a separate tool?
No. This converter handles both directions on one page to avoid duplicate workflows.
How do I know whether my timestamp is seconds or milliseconds?
Modern Unix seconds are usually around 10 digits, while JavaScript-style milliseconds are usually around 13 digits. The source system's documentation is the best confirmation.
Does a Unix timestamp contain a timezone?
No. It identifies an instant relative to UTC. Timezones only affect how that instant is displayed as a local date and clock time.
Why is my converted date completely wrong?
The most common cause is interpreting a milliseconds value as seconds or a seconds value as milliseconds.
Does date-to-timestamp use UTC or my local timezone?
The entered date and time are interpreted in your browser's local timezone. The result then shows the equivalent Unix seconds, Unix milliseconds, UTC display, and ISO timestamp.
What does the Z mean at the end of the ISO timestamp?
Z means zero offset from UTC. It tells readers and systems that the ISO timestamp is expressed as a UTC time.
Can Unix timestamps represent dates before 1970?
Yes. Negative timestamps represent instants before 1970-01-01 00:00:00 UTC, as long as the browser runtime supports the resulting date.