What is a cron expression?

A cron expression is a string of 5 or 6 space-separated fields that defines a recurring schedule: minute, hour, day-of-month, month, and day-of-week. The 6-field variant adds seconds as the first field.

What field syntax is supported?

Each field supports: * (every), comma-separated values (1,5,10), dash ranges (1-5), and step values (*/5 or 1-30/5). These can be combined, e.g., 1,5-10,*/15.

Are the run times shown in UTC?

No. Run times are calculated and displayed in your browser's local timezone using the JavaScript Date API. No server is involved.

What happens with impossible expressions?

If no matching time is found within one year, the tool reports that the expression never fires. This catches impossible dates like February 30.

Is any data sent to a server?

No. All parsing, computation, and rendering happens entirely in your browser. Nothing is transmitted.

Cron Expression Explainer

Name: Cron Expression Explainer
Availability: InStock
Author: Nham Vu

Enter a cron expression to get a plain-English explanation, next 10 run times in your timezone, and a visual schedule grid.

Cron Expression

Expression

5-field (min hr dom mon dow) or 6-field (sec min hr dom mon dow)

Examples

Field Reference

Field	Range	Specials
Seconds	0–59	* , - /
Minutes	0–59	* , - /
Hours	0–23	* , - /
Day (month)	1–31	* , - /
Month	1–12	* , - /
Day (week)	0–7 (0,7=Sun)	* , - /

Enter a cron expression on the left and click Parse to see the explanation.

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Summary

Enter a cron expression to get a plain-English explanation, next 10 run times in your timezone, and a visual schedule grid.

How it works

Enter a cron expression in the input field (5-field standard or 6-field with seconds prefix).
Click Parse to see the plain-English explanation of what the expression means.
Review the next 10 scheduled run times shown in your browser's local timezone.
Scroll down to the visual grid to see which minutes, hours, days, months, and weekdays are active.
Use the Examples dropdown to quickly load common cron patterns.

Use cases

Verify a cron expression before adding it to a server crontab.
Understand what a cron job left by a previous developer actually does.
Check when a scheduled job will next fire in your local time.
Spot impossible expressions (e.g., February 31) before they silently fail.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu