Question 1

What is a cron expression?

Accepted Answer

A cron expression is a string of 5 fields (minute, hour, day-of-month, month, day-of-week) that defines a recurring schedule for automated tasks. For example '0 9 * * 1-5' means every weekday at 9 AM.

Question 2

How do I validate a cron expression?

Accepted Answer

Paste your cron expression in the input field. The parser instantly validates it, explains each field in plain English, and shows the next scheduled run times.

Question 3

What do the special characters mean in cron?

Accepted Answer

* means every value, - defines a range (e.g. 1-5), , lists specific values (e.g. 1,15), and / defines a step (e.g. */15 means every 15 units).

Question 4

What is @daily, @hourly, @weekly in cron?

Accepted Answer

These are special shorthand strings. @daily equals '0 0 * * *' (midnight every day), @hourly equals '0 * * * *', @weekly equals '0 0 * * 0' (Sunday midnight).

Field	Allowed values	Special chars	Example
Minute	0 – 59	* , - /	*/15 = every 15 min
Hour	0 – 23	* , - /	9-17 = 9am to 5pm
Day of month	1 – 31	* , - / ?	1,15 = 1st and 15th
Month	1 – 12	* , - /	*/3 = every quarter
Day of week	0 – 7 (0&7=Sun)	* , - /	1-5 = Mon–Fri

String	Equivalent
@yearly	0 0 1 1 *
@monthly	0 0 1 * *
@weekly	0 0 * * 0
@daily	0 0 * * *
@hourly	0 * * * *
@reboot	Run at startup

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