Standard Cron Format (5 fields)

┌───────────── minute (0-59)
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (0-6, Sun=0)
│ │ │ │ │
* * * * *

Extended Format (6 fields with seconds)

Used by Quartz, Spring, AWS, and many modern schedulers:

┌───────────── second (0-59)
│ ┌───────────── minute (0-59)
│ │ ┌───────────── hour (0-23)
│ │ │ ┌───────────── day of month (1-31)
│ │ │ │ ┌───────────── month (1-12)
│ │ │ │ │ ┌───────────── day of week (0-6, Sun=0)
│ │ │ │ │ │
* * * * * *

Special Characters

*	Any value
,	Value list separator (e.g., 1,3,5)
-	Range of values (e.g., 1-5)
/	Step values (e.g., */15 = every 15)

5-Field Examples (Standard)

* * * * *	Every minute
0 * * * *	Every hour
0 0 * * *	Every day at midnight
0 9 * * 1-5	Weekdays at 9:00 AM
*/15 * * * *	Every 15 minutes

6-Field Examples (With Seconds)

* * * * * *	Every second
0 * * * * *	Every minute
*/30 * * * * *	Every 30 seconds
0 0 * * * *	Every hour
0 0 9 * * 1-5	Weekdays at 9:00 AM

Named Values

Some systems support names:

Months: JAN-DEC   Days: SUN-SAT