Cron Expression Builder
Pattern ToolsBuild and explain cron expressions — see next run times in plain English
Format: minute hour day-of-month month day-of-week
Cron Expression
* * * * *
Plain English
every minute, of every hour
Next 5 Run Times
About Cron Expression Builder
Builds and validates standard Unix cron expressions with a visual interface, plain English translation, and next-run time preview. Type an expression directly or use the field inputs for each cron position — minute, hour, day of month, month, day of week. The explanation output ("At 2:30 AM, Monday through Friday") updates as you type, making it easy to verify the expression matches your intent before deploying it. The next five run times are calculated from the current moment and displayed as absolute timestamps. This is the most important validation step: seeing the actual dates confirms the expression fires when expected and catches off-by-one errors in ranges or step values. Many cron bugs stem from ambiguous interactions between day-of-month and day-of-week fields — some cron implementations use OR logic between them, others use AND logic. Preset expressions cover the most common schedules: every minute, every 5/15/30 minutes, hourly, daily at midnight, daily at noon, weekly on Sunday, monthly on the first, business days only, and several others. These serve as starting points to modify rather than building from scratch. The validator catches obviously invalid values (month 13, hour 25) and warns about expressions that will never fire due to impossible day/month combinations.
How to Use Cron Expression Builder Online
- Paste your data into the input field above
- The result appears instantly in the output area
- Click "Copy" to copy the result to your clipboard
Build and explain cron expressions — see next run times in plain English. Runs 100% client-side — no data is sent to any server.