Cron Schedule Explainer
Explains a cron expression in plain English and shows common presets
About this generator
Decoding a cron expression without documentation is the kind of friction that breaks prod jobs. This tool takes a preset schedule, outputs the exact five-field cron expression, and gives you a plain-English description of when it fires — plus a field-order reminder. The input is a schedule preset: Every minute, Every 15 minutes, Hourly, Daily at midnight, Weekdays at 9am, Weekly on Sunday, or Monthly on the 1st. Pick one and you get the expression with an explanation — for example, `0 9 * * 1-5` paired with "Runs at 09:00 Monday through Friday, skipping weekends." Copy the expression into a crontab, CI schedule, or Kubernetes CronJob spec, and keep the description as an inline comment. That comment is what saves the next engineer from having to decode it again.
How to use
- Pick the schedule you want.
- Click Generate to see the expression and explanation.
- Copy the cron expression into your scheduler.
- Keep the description as a comment for clarity.
Use Cases
- •Setting up a cron job with the right schedule
- •Sanity-checking a cron expression someone else wrote
- •Learning the five-field cron syntax
- •Adding a schedule to a CI or CronJob config
- •Documenting what a scheduled task actually does
Tips
- →Comment every cron line with its plain-English meaning.
- →Confirm the server time zone before trusting a clock time.
- →Avoid scheduling heavy jobs exactly on the hour with everyone else.
- →Use */n for intervals rather than listing each value.
FAQ
what are the five fields in a cron expression
In order: minute (0–59), hour (0–23), day-of-month (1–31), month (1–12), and day-of-week (0–6, where 0 is Sunday). An asterisk means every value; combinations like */15 and 1-5 express intervals and ranges. The output always shows the fields in this order.
which time zone does a cron job use
Traditional cron runs in the server's local time zone, so the same expression fires at different real-world times depending on where the machine is set — a common source of surprises after daylight-saving changes. Many modern schedulers let you specify a zone explicitly.
does this tool support custom intervals beyond the presets
No. The generator maps each preset to a fixed expression from its internal lookup table. It covers the seven most common schedules. If you need a custom interval like every 20 minutes, copy the closest expression and edit the relevant field directly.
can I use these expressions in Kubernetes CronJobs
Yes. Kubernetes CronJobs use the same five-field syntax, so an expression from this tool transfers directly to the schedule field in a CronJob spec, a GitHub Actions schedule trigger, or most job runners.
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