Cron syntax tester
Enter a cron expression to validate its syntax and see exactly what schedule it defines. The tool shows the human-readable meaning and the next run times so you can confirm it matches your intent.
5-field format: minute · hour · day of month · month · day of week
How it works
The tool uses the cronstrue library to translate cron expressions into plain English, and pure JavaScript date arithmetic to compute the next scheduled run times. Everything runs in your browser. Our servers are not involved.
Processing runs in your browser
All parsing and scheduling calculations happen locally in your browser tab. Our servers are not involved at any point.
Related operations
For checking patterns inside log lines or schedules, try the regex tester. To work out the gap between two scheduled runs, use the date calculator. For converting cron timestamps to readable dates, see Unix timestamp.
Frequently asked questions
How do I write a cron expression that runs every hour?
Use 0 * * * *. This runs at minute 0 of every hour. The shorthand @hourly is equivalent.
How do I run a cron job on weekdays only?
Use * * * * 1-5, the last field (day of week) set to 1-5 means Monday through Friday.
Can cron expressions use month names?
Yes. You can use abbreviated month names (JAN, FEB, MAR, etc.) and day names (SUN, MON, TUE, etc.) in place of numbers in the respective fields.
Is there a cron expression for the last day of the month?
Standard cron doesn't natively support 'last day of month'. Some cron implementations (like Quartz) add an L character for this. This tool focuses on standard 5-field POSIX cron syntax.