Unix Timestamp
Convert between Unix epoch seconds and ISO 8601 datetimes
About this calculator
The Unix Timestamp Converter translates between Unix epoch time and ISO 8601 datetimes in both directions. Epoch input auto-detects seconds versus milliseconds by digit count (13+ digits are treated as milliseconds), and results include the ISO string, epoch in seconds and milliseconds, a human-readable UTC string, and the day of the week. ISO input accepts anything Date can parse; unparseable strings return an invalid-input error.
How to use the Unix Timestamp tool
- Enter or paste your input into the field.
- Read the output — it updates instantly as you type.
- Adjust the options, if any, to fit your use case.
- Copy the page URL to share the exact result.
Common examples
- 1735689600 → 2025-01-01T00:00:00.000Z (Wed, 01 Jan 2025 00:00:00 GMT)
- 2025-06-15T12:30:00Z → epoch 1749990600 (a Sunday)
- 1700000000000 (13 digits, auto-detected millis) → 2023-11-14T22:13:20.000Z
Frequently asked questions
How does the Unix Timestamp tool work?
Enter or paste your input and the tool processes it directly in your browser, showing the result immediately. Nothing you type is uploaded to a server — the entire computation happens on your device.
When would I use the Unix Timestamp tool?
It is handy for development, debugging, design and administration tasks — whenever you need this transformation or check done quickly without installing anything or trusting a third-party service with your data.
How reliable are the results?
The tool implements the relevant standard or specification directly, so its output matches what compliant software produces. Edge cases such as empty or malformed input are reported clearly instead of failing silently.
Can I share a specific result with someone else?
Yes. Your input updates the URL, so copying the address bar and sharing the link reopens the tool in the same state for whoever clicks it.