Cron expression explainer
Paste a cron schedule and read it in plain English, with the next run times. It understands standard cron and AWS EventBridge schedules, and runs in your browser.
Runs in your browser, nothing is uploadedTry:,,,
What it means
Next run times (UTC)
Need to write one instead? Use the cron expression generator: pick a schedule in your time zone and get the line for crontab, GitHub Actions, AWS or Kubernetes.
Standard cron: minute hour day-of-month month day-of-week. If both day fields are set, cron runs when either one matches. AWS EventBridge adds a year field, needs a "?" in one of the two day fields, and always runs in UTC. Wrapping the schedule as cron(...) works too.
How to read an EventBridge cron expression
- Paste the schedule. A standard cron has 5 fields; an AWS EventBridge cron has 6, ending with a year field.
- Check "What it means" against what you intended, in plain English.
- Look at the next run times. They are in UTC, so convert to your local time before you trust them.
Example: "every weekday at 6 pm" in AWS
In Linux cron this is 0 18 * * 1-5. In EventBridge it becomes cron(0 18 ? * MON-FRI *): six fields, a question mark in day-of-month, and the time in UTC.
If your team is in UTC+5, 18:00 UTC is 23:00 local time. To run at 18:00 local, use 13 in the hour field, or use EventBridge Scheduler, which accepts a time zone.
Common questions
Why does EventBridge reject my cron?
Usually it is missing the sixth (year) field, or both day fields are set. One of day-of-month and day-of-week must be a question mark.
Are day-of-week numbers the same?
No. Linux cron counts Sunday as 0; EventBridge counts Sunday as 1. Use names such as MON-FRI to avoid the trap.
Does it work for GitHub Actions schedules?
Yes. GitHub Actions uses standard 5-field cron. It runs in UTC unless you add a timezone key next to the cron line.
Read next: Cron vs AWS EventBridge schedules: the 6-field trap
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