Explain any cron expression

Type a 5-field crontab string and get a readable schedule description. Everything runs in your browser — nothing is sent to a server.

Cron expression

Result

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Examples

Integration & Usage

Crontab

* * * * * /path/to/script.sh

Node.js (node-cron)

cron.schedule('* * * * *', () => { ... });

Python (APScheduler)

trigger='cron', minute='*', hour='*'...

Go (robfig/cron)

c.AddFunc("* * * * *", func() { ... })

Cron syntax

Cron schedules tasks on Unix systems. A standard expression has five space-separated fields — minute, hour, day of month, month, and day of week.

min

0–59

hour

0–23

dom

1–31

mon

1–12

dow

0–6

Wildcards

* — any value in the field
, — list of values, e.g. 1,3,5

Ranges & steps

- — range, e.g. 9-17
/ — step interval, e.g. */15

Definitive Guide to Cron: From Unix V7 to Modern Automation

Introduction to Job Scheduling

A Brief History of Cron

Mastering the Five Fields

Operators and Syntax Rules

Common Production Pitfalls

Best Practices for Reliability

Special Characters

L: Stands for "last". In the day-of-week field, it means the last Saturday of the month.
W: Stands for "weekday". Finds the nearest weekday (Monday-Friday) to a given day.
#: Used to specify the "N-th" day of the month, like the second Friday.

Common Patterns

0 0 * * * Midnight
*/15 * * * * Every 15m
0 22 * * 1-5 10PM Weekdays
0 0 1 1 * New Year

FAQ

Does Cron handle timezones?

Standard system cron uses the machine's local time. For cloud environments like AWS or GitHub Actions, schedules are typically executed in UTC. Always verify your server's timezone settings.

What about the 6th or 7th fields?

Standard crontab uses 5 fields. However, some implementations like Quartz (Java) or modern Cron libraries support a 6th field for seconds or a 7th for years. CronParser focuses on the standard 5-field syntax.

How to debug a failing cron job?

Check your system logs (usually /var/log/syslog or journalctl). Ensure your scripts have absolute paths and the correct execution permissions (chmod +x).

Other Tools

DevProfile

Fictional Profile Generator

CPFValidator

Check CPF Validity

Privacy

CronParser parses expressions locally in your browser. Input is never uploaded or stored on remote servers.

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