What does the asterisk (*) mean in cron?

An asterisk means 'every possible value' for that field. For example, * in the minute field means every minute, and * in the day-of-week field means every day of the week.

How do I run a job every 5 minutes?

Use */5 in the minute field: */5 * * * *. The */N syntax means 'every N units'.

What timezone do cron expressions use?

Standard cron uses the server's local timezone. If your scheduling system supports it, you can usually configure the timezone separately. The Toolin visualizer shows times in your browser's local timezone.

How to Write a Cron Expression

4 min readDeveloper

Cron expressions schedule recurring tasks on servers and CI/CD systems. The five-field syntax can be confusing at first. This guide shows you how to build and test cron expressions using a free visual tool that explains each expression in plain language.

Quick Steps

1
Open Cron Visualizer
Go to the Cron Visualizer on Toolin.
2
Enter your expression
Type or build your cron schedule.
3
Read the explanation
Verify the plain-English interpretation.
4
Check next runs
Confirm the upcoming execution times are correct.

Cron Visualizer

Visualize and explain cron schedule expressions

Open Tool

Step-by-Step: Build a Cron Expression

Open the Cron Visualizer tool

Navigate to the Cron Visualizer on Toolin.

Enter or build your expression

Type a cron expression directly or use the visual builder to select minute, hour, day, month, and day-of-week values.

Read the human explanation

The tool translates your cron expression into plain English, such as 'Every day at 3:00 AM'.

Check the next run times

Review the list of upcoming execution times to confirm the schedule is correct.

Cron Expression Syntax

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

0 3 * * *       # Every day at 3:00 AM
*/15 * * * *    # Every 15 minutes
0 9 * * 1-5     # Weekdays at 9:00 AM
0 0 1 * *       # First day of every month at midnight
30 4 * * 0      # Every Sunday at 4:30 AM

Common Cron Scheduling Tasks

Run database backups every night at a specific time.
Schedule CI/CD pipeline runs for business hours only.
Trigger log rotation at the start of each week.
Send recurring reports on the first of each month.
Run health checks every few minutes to monitor uptime.

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Frequently Asked Questions

What does the asterisk (*) mean in cron?: An asterisk means 'every possible value' for that field. For example, * in the minute field means every minute, and * in the day-of-week field means every day of the week.
How do I run a job every 5 minutes?: Use */5 in the minute field: */5 * * * *. The */N syntax means 'every N units'.
What timezone do cron expressions use?: Standard cron uses the server's local timezone. If your scheduling system supports it, you can usually configure the timezone separately. The Toolin visualizer shows times in your browser's local timezone.