Browser-only tool
Unix timestamp converter
Convert seconds or milliseconds since Unix epoch into readable dates, and generate timestamps from date-time values for logs, APIs, and debugging.
Warning: client-side time is useful for conversion and debugging, but it must not be trusted for authentication, authorization, billing, or audit controls.
Use seconds, milliseconds, or an ISO date-time.
Useful And Dangerous Timestamp Cases
Useful for:
- Reading log timestamps.
- Debugging API payloads.
- Converting seconds and milliseconds.
- Comparing UTC and local display.
Do not use for:
- Client-side authorization checks.
- Payment, expiry, or audit decisions without backend validation.
- Ambiguous local-time-only APIs.
Safer alternatives:
- Store server-side UTC timestamps.
- Use explicit ISO strings for APIs.
- Validate security-sensitive time on the backend.
Privacy And Limitations
Timestamp conversion runs locally in your browser and does not upload date values.
- Unix timestamps are usually UTC-based; local display depends on your browser timezone.
- Some APIs use seconds while JavaScript often uses milliseconds.
- Date parsing rules can vary, so critical systems should use explicit ISO timestamps and backend validation.
FAQ
What is a Unix timestamp?
A Unix timestamp counts elapsed time since 1970-01-01 00:00:00 UTC, usually in seconds or milliseconds.
Why do some timestamps look too large?
They may be in milliseconds instead of seconds. JavaScript Date values commonly use milliseconds.
Does timezone change the timestamp?
The timestamp represents an absolute moment. Timezone changes only how that moment is displayed.
Can I use local time for APIs?
Prefer UTC or explicit ISO timestamps for APIs. Local time can be ambiguous around daylight saving changes.
What is dangerous about timestamps?
Timestamps are not authentication or authorization controls. Never trust client-side time for security decisions.