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Cron Expression Builder and Explainer

Pick a schedule or type the five fields and get a ready-to-paste crontab line, a plain-English explanation and the next five run times. Already have a cron line? Paste it to see what it does.

🔒 Runs entirely in your browser. Nothing you type is sent anywhere.

Your cron line

Or explain an existing cron line


Next 5 runs 
    How to use it
    1. Choose a common schedule from Quick start, or type the five fields yourself.
    2. Add the command you want to run (optional).
    3. Check the plain-English line and the next five runs, then copy the line into your crontab with crontab -e.
    To check someone else’s cron job, paste the whole line into Explain an existing cron line.
    The five fields
    ┌──────── minute (0 to 59)
│ ┌────── hour (0 to 23)
│ │ ┌──── day of month (1 to 31)
│ │ │ ┌── month (1 to 12, or jan to dec)
│ │ │ │ ┌ day of week (0 to 7, 0 and 7 are Sunday, or sun to sat)
│ │ │ │ │
* * * * *  command to run

    • * means every value.
    • 1-5 is a range (Monday to Friday in the day of week field).
    • 1,15 is a list (the 1st and 15th).
    • */10 is a step (every 10 minutes in the minute field).
    • Shortcuts such as @daily, @weekly and @reboot also work.
    Common gotchas
    • Cron uses the server’s time zone, not yours. The next runs shown here use your browser’s time zone, so check timedatectl on the server if they differ.
    • Day of month and day of week are combined with OR when both are set. 0 9 1 * 1 runs on the 1st of the month and every Monday, not only Mondays that fall on the 1st.
    • Cron has a minimal environment. Use full paths (/usr/bin/aws, not aws) and set any variables your script needs. Our AWS CLI and cron guide covers this.
    • Log the output so you can see failures: add >> /var/log/myjob.log 2>&1 to the end of the command.
    FAQ
    Does it support seconds?
No. Standard cron runs at most once a minute. For anything faster, use a systemd timer or a loop in a script.
    Does it work for Synology Task Scheduler or Kubernetes CronJobs?
Kubernetes CronJobs use the same five fields, so yes. Synology’s Task Scheduler uses its own screens, but the logic is the same.
    Is anything sent to a server?
No. Everything is worked out in your browser.