One cron expression, every platform. Paste a schedule, read it in plain English, check the next runs in your timezone, and copy it formatted for crontab, Kubernetes, GitHub Actions, AWS EventBridge or Terraform.
| * | every value |
| */15 | every 15th value (0, 15, 30, 45) |
| 1-5 | range — Monday to Friday in the weekday field |
| 1,15 | list — the 1st and the 15th |
| 0-6 / SUN-SAT | weekdays: 0 or 7 = Sunday, names accepted |
| JAN-DEC | month names accepted |
| @daily @hourly @weekly @monthly @yearly | shortcuts |
A cron expression is a five-field text schedule — minute, hour, day of month, month, day of week — used by Unix crontab, Kubernetes CronJobs, GitHub Actions and most schedulers to define when a job runs. 0 9 * * 1-5 means 9:00am, Monday to Friday.
EventBridge uses six fields (adding a year), numbers weekdays 1–7 starting at Sunday instead of 0–6, and requires a ? in either the day-of-month or day-of-week position. That's why a copied crontab line fails in EventBridge — the converter above handles all three differences.
Yes, always. GitHub Actions does not observe your repo's timezone or daylight saving. If you want 9am Sydney time, you must write the UTC equivalent — and revisit it when DST flips.
Since Kubernetes 1.27, spec.timeZone is stable. Set it to an IANA zone like Australia/Sydney and the schedule follows that zone, including DST changes. The Kubernetes export above includes it.
Usually one of three things: the classic day-of-month vs day-of-week trap (when both are restricted, standard cron runs when either matches), a server clock in UTC while you assumed local time, or DST shifting the wall-clock hour. The plain-English readout above makes the first one visible.