Unix Timestamp Converter: Epoch to Date & Back (UTC)
timestamp ↔ dateConvert Unix timestamps (epoch seconds) to human-readable dates and back. Shows ISO 8601, relative time, and millisecond precision for US developers and log analysis.
US Exclusive Use Cases
This Unix timestamp converter serves American developers, sysadmins, and data analysts:
- API log analysis: Decode Unix timestamps in US server logs and API responses into readable dates
- Database timestamp conversion: Convert epoch columns in US-hosted databases to local time for reports
- Debugging webhooks: Translate Unix timestamps from Stripe, PayPal, and other US payment webhooks
- Cron job scheduling: Verify Unix timestamps when configuring US server cron jobs and scheduled tasks
- JWT & token expiry: Check exp claims in JWT tokens issued by US auth providers
US vs Global Calculation Differences
Unix timestamps are universal, but US usage has distinct patterns:
- UTC baseline: Unix epoch (Jan 1, 1970 UTC) is timezone-agnostic, but US developers often convert to ET/PT for display
- Second vs millisecond: US APIs commonly use seconds (Unix) while JavaScript uses milliseconds — this tool shows both
- DST interaction: When converting epoch to US local time, DST shifts the displayed hour but not the underlying timestamp
- Log timezone: US server logs in UTC require conversion to local ET/CT/MT/PT for human review
Common Calculation Mistakes
Common mistakes: confusing seconds with milliseconds (off by 1000x), assuming the timestamp is in local time (Unix epoch is always UTC), and mishandling DST when displaying converted times. Always confirm whether your source system uses seconds or milliseconds before converting.
Tool Algorithm & Precision Explanation
The converter handles both directions with full precision:
- Timestamp to date: multiplies epoch seconds by 1000 to create a JavaScript Date, then formats for US display
- Date to timestamp: divides the Date milliseconds by 1000 and floors to integer seconds
- ISO 8601 output: shows the UTC ISO string for universal interchange
- Relative time: computes "X days ago" or "X days from now" from the current moment
- Millisecond display: also shows the millisecond value for JavaScript and database use
US Developer Reference Table
Common Unix timestamp anchors and their US developer uses:
| Epoch Anchor | Timestamp | Common Use |
|---|---|---|
| Unix epoch start | 0 | Jan 1, 1970 UTC |
| Y2K (Jan 1, 2000) | 946684800 | Legacy system boundary |
| Jan 1, 2026 | 1767225600 | Current-year logs |
| Jan 1, 2038 | 2147483648 | 32-bit overflow (Y2038) |
| Typical API response | Variable | Webhook & API parsing |
Frequently Asked Questions
How do I convert a Unix timestamp to a readable date?
Select "Timestamp → Date" mode, enter your Unix timestamp in seconds, and click Convert. The tool shows the formatted US date and time, the ISO 8601 string, and a relative time like "5 days ago".
How do I convert a date to a Unix timestamp?
Select "Date → Timestamp" mode, enter a date and time, and click Convert. The tool returns the Unix timestamp in seconds plus the millisecond value for JavaScript use.
Does the Unix timestamp use seconds or milliseconds?
Unix timestamps are in seconds by convention. JavaScript Date uses milliseconds, so this tool multiplies by 1000 when converting to a date and shows both seconds and milliseconds values.
What timezone is a Unix timestamp in?
Unix timestamps are always based on UTC (Coordinated Universal Time). The epoch is January 1, 1970 00:00:00 UTC. When displayed, the formatted time reflects your local timezone.
What is the Year 2038 problem?
On January 19, 2038, 32-bit Unix timestamps overflow (max value 2147483647). Systems using 32-bit integers will break. This tool uses 64-bit numbers and is unaffected.
Can I use this for API and webhook debugging?
Yes. Paste the timestamp field from any US API response (Stripe, PayPal, GitHub, etc.) to decode it into a readable date for debugging and log analysis.