UNIX Time Converter
Convert UNIX timestamps (seconds or milliseconds) to UTC/local time and back.
The tool auto-detects whether the input is 10-digit seconds or 13-digit milliseconds
and updates all fields in real time with no API calls.
View ISO 8601 output, human-readable strings, and the detected weekday.
Quick actions let you copy any field, jump to the current time, auto-refresh every second, or clear inputs.
All calculations are done in your browser using the native Date and Intl APIs.
Auto-detects seconds or milliseconds
Auto-syncs with UNIX input. Accepts local time.
Unix Timestamp Converter
Unix timestamps appear in logs, databases, API responses, JWT claims, analytics exports, and monitoring alerts. This converter turns second-based or millisecond-based timestamps into readable dates and helps you convert dates back into timestamp values.
Common use cases
- Debug logs: Convert raw timestamps into human-readable times during incident investigation.
- Check API fields: Review
created_at,updated_at,iat,exp, and expiration values. - Validate stored data: Confirm whether database timestamps match expected user actions or system events.
Seconds vs milliseconds
A 10-digit timestamp is often seconds, while a 13-digit timestamp is often milliseconds, but systems vary. If the resulting date looks far in the past or future, check whether you are using the correct unit.
Articles for this tool
Unix Time and Timezone Essentials: What Every Engineer Should Know
Explore Unix time definitions, the difference between seconds and milliseconds, handling timezones (UTC/JST), and common pitfalls in software development.
How to Convert Milliseconds, Seconds, Minutes, and Hours for Timeouts and TTLs
Convert time units for API timeouts, cache TTLs, retry delays, polling intervals, and monitoring settings without mixing up milliseconds and seconds.
Check JWT expiration and payload before an API review
A practical workflow for decoding JWTs, checking exp, iat, aud, and scope, and catching authentication issues before review.
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