Cron expression explainer
Explain a 5-field cron expression and show upcoming UTC run times. No commands are executed.
The expression stays in your browser. No server request. Analytics never receive the expression text.
Format: minute hour day-of-month month day-of-week
Meaning: minute 0; hour 0, 6, 12, 18; every day of the month; every month; every day of the week
Supported syntax is classic 5-field cron (minute hour day-of-month month day-of-week) with lists, ranges, and steps. This is not a guarantee that every platform (systemd, GitHub Actions, cloud schedulers) uses identical rules.
Next runs (UTC)
2026-09-04T18:00:00Z2026-09-05T00:00:00Z2026-09-05T06:00:00Z2026-09-05T12:00:00Z2026-09-05T18:00:00Z
Input privacy
The expression stays in your browser. No server request. Analytics never receive the expression text.
Methodology
Parses classic 5-field cron (minute hour day-of-month month day-of-week) with lists, ranges, and steps. Next runs are projected minute-by-minute in UTC. Day-of-month and day-of-week restrictions follow common OR semantics and are called out in warnings.
A cron expression describes when a job should run. Pair it with a heartbeat monitor to learn whether it actually ran.
Limitations
- Not every platform uses identical cron syntax
- Seconds fields and some extensions are unsupported
- Timezone conversions around DST need human care
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