Developers
Cron Expression Explainer
Parse cron expressions and show the next scheduled run times in plain language.
100% client-side — your data never leaves this tab
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What is Cron Expression Explainer?
Cron Explainer translates cron expressions into plain-language schedules and upcoming run times. It helps developers and DevOps teams validate automation timing before deploying jobs.
Cron parsing and schedule explanation run entirely in-browser.
How to use Cron Expression Explainer
- 1Paste a 5-field cron expression like `0 9 * * 1-5`.
- 2Review human-readable schedule interpretation.
- 3Check next run timestamps in your local timezone.
- 4Fix invalid fields and retest until schedule matches intent.
Examples
Weekday morning run
0 9 * * 1-5 -> Every weekday at 09:00
Quarter-hour trigger
*/15 * * * * -> Every 15 minutes
Tips & common mistakes
- Confirm server timezone to avoid production timing surprises.
- Use explicit ranges/lists for clarity in team-owned jobs.
- Test daylight-saving edge cases for global deployments.
Who uses this tool?
- DevOps teams validating backup and cleanup schedules.
- Backend engineers checking notification and ETL cron jobs.
- SREs debugging missed or duplicated periodic tasks.
Frequently asked questions
- What do the five cron fields represent?
- They represent minute, hour, day of month, month, and day of week in that order.
- Why did my cron run at the wrong time?
- Timezone mismatch is a common cause. Verify scheduler timezone and DST behavior.
- How do I run a job every weekday?
- Use an expression like `0 9 * * 1-5` for 9 AM Monday through Friday.
- Can this parse Quartz-style cron with seconds?
- This explainer focuses on standard 5-field cron. Quartz 6/7-field syntax may need separate validation.
- What does `*/5` mean in cron?
- It means 'every 5 units' of that field, such as every 5 minutes when used in the minute position.