Cron Expression Explainer

Explain common five-field cron expressions and catch basic schedule mistakes before adding a job to production.

Cron explanation 

        

    

                

            
                    

                        
How to use this tool

                        
    
                                                            
  1. Paste a five-field cron expression such as */5 * * * *.
    2. 
                                                            
  2. Check the human-readable explanation and validation notes.
    3. 
                                                            
  3. Use the examples when building common schedules.
    4. 
                                                    

                    


                    

                        
Common mistakes

                        
    
                                                            
  • Confusing day-of-month and day-of-week fields.
    • 
                                                            
  • Forgetting that system cron usually uses server time, not user local time.
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  • Using six-field syntax in a five-field cron environment.
    • 
                                                    

                    


                    

                        
FAQ

                        

                                                            

                                    Does this support every cron dialect?
                                    
No. It focuses on common five-field Unix cron patterns.

                                

                                                            

                                    Does cron include seconds?
                                    
Classic Unix cron does not. Some schedulers add a seconds field.

                                

                                                            

                                    Can I use names like MON or JAN?
                                    
Many cron systems support names, but this first version focuses on numeric and common symbolic patterns.

                                

                                                    

                    


                        

        
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Related guides and fixes

        

                                                
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Last updated: May 17, 2026