Unix Timestamp Converter
Convert Unix timestamps to dates and dates back to seconds or milliseconds.Developer ToolsUnix timestamp converter
Convert Unix seconds or milliseconds into readable dates, or paste an ISO date to get its timestamp.
Examples: 1700000000, 1700000000000, 2026-01-01T00:00:00Z
About this tool
Epoch values are easy to misread by a factor of a thousand. Enter a timestamp and see both UTC and your local time, or paste a date and get both its seconds and milliseconds values.
How to use the Unix Timestamp Converter tool
- Enter a timestamp. Type a Unix timestamp in seconds or milliseconds, or paste a date such as 2026-01-01T00:00:00Z. The unit is detected automatically.
- Read the dates. Click Convert to see the UTC and local date-times, the ISO form and both timestamp units.
- Or go the other way. Use the Use now button to fill in the current time, or paste any date to convert it back into seconds and milliseconds.
Supported formats
Input
- Unix timestamp in seconds
- Unix timestamp in milliseconds
- A date string such as 2026-01-01T00:00:00Z
Output
- UTC date-time
- Local date-time with offset
- Seconds and milliseconds
Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.
Frequently asked questions
How do I know if my value is seconds or milliseconds?
Values around 1.7 billion are seconds; values around 1.7 trillion are milliseconds. The tool detects the unit from the magnitude and shows both values, so you can confirm which one you meant.
Which timezone is used?
Both UTC and your browser's local timezone are displayed, so you never have to guess which one you are looking at.
Are negative timestamps allowed?
Yes. Dates before 1970 are handled and shown as expected.
What about dates far in the future?
The valid JavaScript date range applies; out-of-range values are rejected with a clear message.
Privacy
Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.
No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.
Known limitations
- Timezone conversion follows your device's current timezone setting.
- Dates outside the JavaScript Date range are rejected.
- Leap seconds are not modelled; the standard POSIX-style epoch is used.
Related tools
Other free tools from the same collection.