Cron Expression Builder
Build cron expressions visually with natural language description and next executions. No sign-up.
Cron Builder
Presets
Fields
Cron expression
* * * * *Next executions
- 1Mon, Mar 23, 2026, 03:03 AM
- 2Mon, Mar 23, 2026, 03:04 AM
- 3Mon, Mar 23, 2026, 03:05 AM
- 4Mon, Mar 23, 2026, 03:06 AM
- 5Mon, Mar 23, 2026, 03:07 AM
Built by
Miguel Ángel Colorado Marin
Built by
Miguel Ángel Colorado Marin
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
How to use the cron builder?
- 1
Configure each field
Enter a value for each of the 5 cron fields: minute, hour, day of month, month and day of week. You can use * for 'any value', specific numbers, ranges (1-5), intervals (*/15) or comma-separated lists.
- 2
Use the quick presets
Under each field there are quick-access buttons with the most common values. For example, */5 for every 5 units, or 0 for zero value. Click any preset to fill the field instantly.
- 3
Read the natural language description
The tool automatically generates a description in Spanish and English of what the expression does. For example: 'At 09:00 on Mondays' or 'Every 15 minutes'. This helps you verify the expression is correct.
- 4
Check the next executions
You'll see the next 5 dates and times when the task will run according to the configured cron expression. This is very useful for verifying that the days and times match what you expected.
Frequently asked questions
What is a cron expression?
A cron expression is a text string made up of 5 space-separated fields that defines when a scheduled task should run on Unix/Linux systems. The fields are: minute (0-59), hour (0-23), day of month (1-31), month (1-12) and day of week (0-6, where 0=Sunday).
What does the asterisk (*) mean in cron?
The asterisk means 'any value'. For example, * * * * * means 'run every minute'. If you put 0 * * * * it means 'at minute 0 of every hour', i.e. at the start of every hour.
How do I specify an interval like every 15 minutes?
Use the */N notation to specify an interval. For example, */15 in the minute field means 'every 15 minutes'. */2 in the hour field means 'every 2 hours'. This notation is equivalent to 0,15,30,45 in the case of every 15 minutes.
Can I specify multiple values in a field?
Yes, you can use commas to list specific values (1,15,30) and hyphens for ranges (1-5). You can also combine them: 1-5,10,15 means 'days 1 through 5, the 10th and the 15th'.
Does this tool work offline?
Yes. All cron expression calculation, natural language description generation and next-execution calculation are done entirely in your browser with pure JavaScript. No data is sent to any server.
Embed the cron builder on your site
Embed this cron expression builder in any web page with a simple iframe:
<iframe
src="https://miguelacm.es/embed/cron-builder"
width="100%"
height="600"
frameborder="0"
title="Cron Builder"
></iframe>