Cron Job Generator
Build cron job expressions visually without memorizing the syntax. Generate, validate, and test cron schedules online. Supports standard 5-field and extended 6-field cron.
Quick Presets
Allowed: 0-59, *, /, -, ,
Allowed: 0-23, *, /, -, ,
Allowed: 1-31, *, /, -, ,
Allowed: 1-12, *, /, -, ,
Allowed: 0-6 (Sun-Sat), *, /, -, ,
Frequently Asked Questions
What is a cron job?+
A cron job is a scheduled task that runs automatically at specified times on a Unix-based server. The name comes from Chronos (the Greek god of time). Cron jobs are commonly used for automated backups, sending digest emails, clearing temporary files, syncing databases, generating reports, and triggering API calls at regular intervals. They require no manual intervention once set up.
What does '*/5 * * * *' mean in cron syntax?+
This expression runs a task every 5 minutes. The five fields in a standard cron expression are (left to right): minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6, where 0 = Sunday). The asterisk (*) means 'every', and */5 means 'every 5th unit'. So */5 * * * * = every 5 minutes, every hour, every day.
How do I run a cron job every day at midnight?+
Use the expression: 0 0 * * * — this means 'at minute 0, hour 0, every day'. Alternatively, many cron systems support shorthand like @daily or @midnight which are identical. To run at 2:30 AM instead, use: 30 2 * * *.
What is the difference between 5-field and 6-field cron?+
Standard Unix cron uses 5 fields (minute, hour, day, month, weekday). Some systems like AWS CloudWatch Events, Spring (Java), and Quartz Scheduler add a 6th field for seconds at the beginning: second minute hour day month weekday. This tool supports both formats and will show you which format your target system uses.
How do I schedule a cron job to run on weekdays only?+
Use the day-of-week field (5th field). Monday-Friday is represented as 1-5. Example: 0 9 * * 1-5 runs at 9 AM every weekday. For weekends only: 0 9 * * 6,0 runs at 9 AM on Saturday and Sunday.
Can cron run a job every 30 seconds?+
Standard 5-field cron cannot schedule tasks more frequently than once per minute. To run every 30 seconds, you need either a 6-field cron (if your system supports it), or run the job every minute and have your script sleep for 30 seconds and run a second time. AWS Lambda and similar services have their own scheduling mechanisms that support sub-minute intervals.