Cron Expression Generator
Build cron expressions visually with an intuitive interface. Generate cron syntax with human-readable descriptions and preview next run times.
Visual Builder
Build cron expressions using intuitive dropdowns and inputs.
Human Readable
See plain English descriptions of your cron expressions instantly.
Preview Times
View the next 5 execution times to verify your schedule.
Understanding Cron Expressions
A cron expression is a string consisting of five fields separated by spaces that describe individual details of the schedule. Each field represents a unit of time: minutes, hours, day of month, month, and day of week.
Cron Expression Format
| | | | |
| | | | └─── Day of Week (0-6, Sunday=0)
| | | └────── Month (1-12)
| | └───────── Day of Month (1-31)
| └──────────── Hour (0-23)
└─────────────── Minute (0-59)
Special Characters
- * (asterisk): Matches all values in the field (every minute, hour, day, etc.)
- - (dash): Defines a range (e.g., 1-5 means 1,2,3,4,5)
- , (comma): Specifies a list of values (e.g., 1,3,5)
- / (slash): Specifies increments (e.g., */5 in minutes means every 5 minutes)
Common Examples
0 0 * * * - Daily at midnight
0 */6 * * * - Every 6 hours
30 9 * * 1-5 - 9:30 AM on weekdays
0 0 1 * * - First day of every month at midnight
*/15 * * * * - Every 15 minutes
Use Cases
Cron expressions are commonly used for automated backups (scheduling nightly database backups), data synchronization (syncing data between systems at regular intervals), report generation (creating daily or weekly reports), cleanup tasks (removing old files or logs), monitoring and alerts (checking system health periodically), and batch processing (running large jobs during off-peak hours).
Best Practices
- Always test your cron expressions before deploying to production
- Use specific times rather than wildcards when possible for predictability
- Consider timezone implications when scheduling jobs
- Document your cron schedules with comments in your crontab
- Monitor cron job execution and set up alerts for failures
- Avoid scheduling intensive tasks during peak hours
FAQ
A cron expression is a string format used to define time-based schedules in Unix-like operating systems. It consists of five fields (minute, hour, day of month, month, day of week) that specify when a task should run.
Use the expression: */5 * * * * - This means "every 5 minutes, every hour, every day". The */5 in the minutes field creates an interval of 5 minutes.
The asterisk (*) is a wildcard that matches all possible values for that field. For example, * in the hours field means "every hour", and * in the day of week field means "every day of the week".
Yes! Use 1-5 in the day of week field. For example, "0 9 * * 1-5" runs at 9 AM on Monday through Friday. Monday is 1 and Friday is 5.
Use: 0 0 1 * * - This runs at midnight (0 hours, 0 minutes) on the 1st day of every month. You can adjust the hour and minute fields as needed.