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Date & Time Cheatsheet
Cron syntax, ISO 8601 formats, Unix timestamp values, timezone offsets.
Cron Syntax
Format: minute hour day-of-month month day-of-week
| Expression | Meaning |
|---|---|
| * * * * * | Every minute |
| 0 * * * * | Every hour (at :00) |
| 0 0 * * * | Daily at midnight |
| 0 9 * * 1-5 | Weekdays at 09:00 |
| 0 0 * * 1 | Every Monday at midnight |
| */5 * * * * | Every 5 minutes |
| 0 0 1 * * | First day of every month |
| 0 0 1 1 * | January 1st at midnight |
| 30 6 * * 1,3,5 | Mon/Wed/Fri at 06:30 |
| @hourly | Alias for 0 * * * * |
| @daily | Alias for 0 0 * * * |
| @weekly | Alias for 0 0 * * 0 |
| @monthly | Alias for 0 0 1 * * |
| @yearly | Alias for 0 0 1 1 * |
ISO 8601 Date Formats
| Format | Example | Notes |
|---|---|---|
| Date | 2026-06-16 | YYYY-MM-DD |
| Time | 14:30:00 | HH:MM:SS |
| DateTime (UTC) | 2026-06-16T14:30:00Z | Z = UTC offset |
| DateTime (offset) | 2026-06-16T14:30:00+05:30 | IST example |
| Week | 2026-W25 | Week number |
| Duration | P1Y2M3DT4H5M6S | 1 year, 2 months, 3 days, 4h 5m 6s |
| Interval | 2026-01-01/2026-06-30 | Date range |
Unix Timestamp Reference
| Value | Meaning |
|---|---|
| 0 | Unix epoch: 1970-01-01T00:00:00Z |
| 86400 | 1 day in seconds |
| 604800 | 1 week in seconds |
| 2592000 | 30 days in seconds |
| 31536000 | 365 days in seconds |
| 1748995200 | ~2026-06-04 (example current) |
| 2147483647 | Year 2038 (32-bit overflow boundary) |
Common Timezone Offsets
| Timezone | Offset | Region |
|---|---|---|
| UTC | +00:00 | Universal |
| EST | -05:00 | US Eastern |
| EDT | -04:00 | US Eastern (summer) |
| PST | -08:00 | US Pacific |
| CET | +01:00 | Central Europe |
| IST | +05:30 | India |
| JST | +09:00 | Japan |
| AEST | +10:00 | Australia Eastern |