Unix Timestamp Converter
Convert Unix epoch timestamps in seconds or milliseconds to human date/time.
Number of seconds (or milliseconds) elapsed since Jan 1, 1970 UTC
Unix timestamp 1705320000 (seconds) corresponds to 2024-01-15T12:00:00.000Z (2 years ago).
How It Works
The Unix Timestamp Converter translates between POSIX/Unix integer timestamps and human-readable calendar dates in UTC and local time.
It automatically differentiates between 10-digit second timestamps (standard in backend databases and Unix systems) and 13-digit millisecond timestamps (standard in JavaScript).
Formula & Calculation
Unix Epoch Definition
Unit Conversion Formula
Step-by-Step Example
Example: Converting Timestamp 1705320000
Translating timestamp 1,705,320,000 to UTC calendar time:
10 digits → Seconds precision→ 1,705,320,000 seconds1,705,320,000 × 1,000→ 1,705,320,000,000 msEpoch + 1,705,320,000 seconds→ 2024-01-15T12:00:00.000ZTimestamp 1705320000 corresponds to Monday, January 15, 2024, at 12:00:00 PM UTC.
Assumptions & Edge Cases
- Year 2038 Problem (Y2038): Legacy 32-bit signed integers overflow on January 19, 2038, at 03:14:07 UTC. EverydayNumbers uses 64-bit IEEE double and decimal numbers, correctly supporting timestamps billions of years into the past and future.
- Negative Timestamps: Negative timestamps represent dates prior to the January 1, 1970 epoch (for example, -315619200 represents January 1, 1960).
Frequently Asked Questions
Why do JavaScript timestamps have 13 digits while Unix has 10?
Standard Unix timestamps count seconds since the 1970 epoch (yielding 10 digits in the 2020s). JavaScript’s `Date.now()` counts milliseconds since the epoch, appending three additional digits.