What does the asterisk (*) mean in cron?

The asterisk (*) is a wildcard that means "every" or "any value". For example, * * * * * runs every minute because all fields accept any value. Using 0 * * * * runs at minute 0 of every hour.

How do I run a cron job every 5 minutes?

Use */5 * * * * to run every 5 minutes. The / operator defines a step value. Similarly, */10 * * * * runs every 10 minutes.

What is the difference between cron and crontab?

Cron is the daemon (background service) that executes scheduled tasks. Crontab (cron table) is the configuration file where you define the schedule and commands. You edit the crontab using crontab -e on Unix systems. For tracking individual job runs, consider assigning each execution a UUID as a unique identifier.

How do I schedule a job for specific days of the week?

Use the fifth field (day of week) with values 0-6 where 0 is Sunday. For weekdays only, use 0 9 * * 1-5 (Monday to Friday at 9 AM). For weekends, use 0 9 * * 0,6 (Saturday and Sunday). Our Timestamp Converter can help you work with execution times across time zones.

Do cron expressions support seconds?

Standard Unix cron uses 5 fields and does not support seconds. However, some systems like Quartz Scheduler, Spring, and AWS EventBridge support a 6-field format with seconds as the first field. Our builder supports both formats.

Cron Expression Builder

Free online cron expression builder and parser with presets, syntax reference, and next run preview

Cron Expression Builder

Cron Expression

* * * * *

Minute

0-59

Hour

0-23

Day (Month)

1-31

Month

1-12

Day (Week)

0-6

Common Presets

Next Scheduled Runs

1. 2/9/2026, 5:43:10 PM

2. 2/9/2026, 5:44:10 PM

3. 2/9/2026, 5:45:10 PM

4. 2/9/2026, 5:46:10 PM

5. 2/9/2026, 5:47:10 PM

Syntax Reference

Special Characters

* - Any value

, - Value list (1,3,5)

- - Range (1-5)

/ - Step values (*/15)

Examples

0 0 * * 0 - Weekly on Sunday

*/5 * * * * - Every 5 minutes

0 2 1 * * - 2am on 1st of month

0 9-17 * * 1-5 - 9am-5pm weekdays

Cron Guide

What is a Cron Expression?

A cron expression is a string of five or six fields that define a schedule for automated tasks. Originally developed for Unix systems, cron expressions are now used across all platforms including Linux servers, cloud services (AWS, Google Cloud, Azure), and CI/CD pipelines.

The standard format uses five fields: minute hour day-of-month month day-of-week. Some systems add a sixth field for seconds. Each field accepts specific values, ranges, or special characters like * (any), , (list), and / (step).

Common Cron Schedule Examples

Here are frequently used cron expressions:

0 * * * * - Every hour at minute 0
0 0 * * * - Every day at midnight
0 9 * * 1-5 - Every weekday at 9:00 AM
0 0 1 * * - First day of every month at midnight
*/15 * * * * - Every 15 minutes
0 0 * * 0 - Every Sunday at midnight

Cron Expression Syntax Reference

Each field in a cron expression has specific allowed values:

Field	Values	Special Characters
Minute	0-59	* , - /
Hour	0-23	* , - /
Day of Month	1-31	* , - / L W
Month	1-12 or JAN-DEC	* , - /
Day of Week	0-6 or SUN-SAT	* , - / L #

Frequently Asked Questions

Timestamp

Unix time converter

Regex

Test patterns & matches

UUID

Generate v4, v7, ULID

JSON

Validate, format & convert JSON

Cron Expression Builder

Cron Expression Builder

Common Presets

Next Scheduled Runs

Syntax Reference

Cron Guide

What is a Cron Expression?

Common Cron Schedule Examples

Cron Expression Syntax Reference

Frequently Asked Questions

What does the asterisk (*) mean in cron?

How do I run a cron job every 5 minutes?

What is the difference between cron and crontab?

How do I schedule a job for specific days of the week?

Do cron expressions support seconds?

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Frequently Asked Questions

What does the asterisk (*) mean in cron?

How do I run a cron job every 5 minutes?

What is the difference between cron and crontab?

How do I schedule a job for specific days of the week?

Do cron expressions support seconds?