What does * * * * * mean in cron?

Five asterisks means "every minute of every hour of every day of every month on every day of the week." It is the most frequent possible cron schedule — your command runs once per minute, 1,440 times per day. This is rarely what you want in production but useful for testing.

How do I run a cron job every 5 minutes?

Use */5 in the minute field: */5 * * * * This means "every 5 minutes, every hour, every day." The */5 syntax divides the minute range (0-59) into 5-minute steps: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55.

How do I run a cron job at midnight?

Use 0 0 * * * which means "at minute 0 of hour 0 (midnight) every day." If you want 12:30 AM instead, use 30 0 * * *. Remember that cron uses 24-hour time, so midnight is hour 0 and noon is hour 12.

How do I schedule a job for weekdays only?

Add 1-5 in the day-of-week field. For example, 0 9 * * 1-5 runs at 9:00 AM Monday through Friday. The day-of-week field uses 0 for Sunday through 6 for Saturday (some systems also accept 7 for Sunday).

What is the difference between */2 and 0-23/2 in the hour field?

They produce the same result — both run every 2 hours. */2 is shorthand for "start at 0, step by 2" which gives you hours 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22. The 0-23/2 syntax is explicit about the range. Use whichever is clearer to your team.

Can I combine multiple schedules in one cron expression?

Not in a single expression. Each cron line is one schedule. To run a job at both 9 AM and 5 PM, you can use a comma in the hour field: 0 9,17 * * *. But for truly different schedules (like every Monday at 9 AM AND every first of the month at noon), create two separate crontab entries pointing to the same script.

How do I run a job on the last day of every month?

Standard cron has no "last day of month" syntax. The common workaround is to schedule it for day 28-31 and add a check in your script: if the current day equals the last day of the month, run the job. Alternatively, some extended cron implementations (like Quartz) support an L modifier for this.

What timezone does cron use?

Cron uses the system timezone by default. On Linux, check with "timedatectl" or "cat /etc/timezone". If your server is set to UTC but you want jobs to run at 9 AM Eastern, you need to calculate the UTC equivalent (1 PM or 2 PM UTC depending on daylight saving). Some systems like GitHub Actions always use UTC.

Crontab Cheat Sheet — 25 Common Cron Schedules Ready to Copy

Last updated: April 20266 min readDeveloper Tools

Cron expressions control when automated tasks run on servers, CI/CD pipelines, and cloud schedulers. Here are 25 common cron schedules you can copy and paste directly into your crontab, GitHub Actions, or any scheduler that accepts standard cron syntax.

Minute Intervals

Expression	Schedule	Use Case
* * * * *	Every minute	Testing, real-time monitoring (use carefully)
/2 * * *	Every 2 minutes	Frequent health checks, queue processing
/5 * * *	Every 5 minutes	API polling, uptime monitoring, cache refresh
/10 * * *	Every 10 minutes	Data sync, metrics collection
/15 * * *	Every 15 minutes	Dashboard updates, feed aggregation
/30 * * *	Every 30 minutes	Email queue processing, report snapshots

Hourly Intervals

Expression	Schedule	Use Case
0 * * * *	Every hour (at :00)	Log aggregation, hourly reports
0 /2 * *	Every 2 hours	Database cleanup, temp file purge
0 /3 * *	Every 3 hours	External API data refresh
0 /4 * *	Every 4 hours	Sitemap regeneration, search index update
0 /6 * *	Every 6 hours	Cache clearing, CDN purge
0 /12 * *	Every 12 hours (midnight and noon)	Certificate checks, DNS refresh

Daily Schedules

Expression	Schedule	Use Case
0 0 * * *	Every day at midnight	Database backups, log rotation
0 2 * * *	Every day at 2:00 AM	Full backups (low traffic window)
0 9 * * *	Every day at 9:00 AM	Daily report generation and email
30 8 * * *	Every day at 8:30 AM	Team notification / standup reminder

Weekly, Monthly & Beyond

Expression	Schedule	Use Case
0 9 * * 1	Every Monday at 9:00 AM	Weekly summary report
0 9 * * 1-5	Weekdays at 9:00 AM	Business-hours-only tasks
0 17 * * 5	Every Friday at 5:00 PM	End-of-week cleanup, deploy freeze check
0 0 * * 0	Every Sunday at midnight	Weekly log rotation, full backup
0 0 1 * *	First of every month at midnight	Monthly invoicing, subscription billing
0 10 1 * *	First of every month at 10:00 AM	Payment reminders, monthly reports
0 0 1 1,4,7,10 *	Quarterly (Jan, Apr, Jul, Oct)	Quarterly audits, compliance reports
0 0 1 1 *	January 1st at midnight	Annual cleanup, yearly reports

Build custom cron expressions with a visual tool — no syntax memorization.

Open Cron Generator

Reading Cron Expressions — Quick Decoder

Every cron expression reads left to right: minute, hour, day-of-month, month, day-of-week.

0 9 * * 1-5 — minute 0, hour 9, any day, any month, Mon-Fri = "9:00 AM on weekdays"
*/15 9-17 * * * — every 15 min, hours 9-17, any day = "every 15 minutes during business hours"
0 0 1,15 * * — minute 0, hour 0, days 1 and 15 = "midnight on the 1st and 15th of each month"
30 4 * * 0 — minute 30, hour 4, any day, any month, Sunday = "4:30 AM every Sunday"

When in doubt, paste any expression into the Cron Generator to see the human-readable translation.

Cron Shorthand (Non-Standard)

Some systems accept these shorthand aliases instead of five-field expressions:

Shorthand	Equivalent	Meaning
@yearly (or @annually)	0 0 1 1 *	Once a year at midnight on January 1st
@monthly	0 0 1 * *	Once a month at midnight on the 1st
@weekly	0 0 * * 0	Once a week at midnight on Sunday
@daily (or @midnight)	0 0 * * *	Once a day at midnight
@hourly	0 * * * *	Once an hour at the top of the hour
@reboot	N/A	Once at system startup (not time-based)

Note: These shorthands work in Linux crontab and some schedulers, but not in GitHub Actions, AWS CloudWatch, or Kubernetes CronJobs. Stick to five-field expressions for maximum compatibility.

Common Mistakes

Using * in the minute field when you meant 0 — * 9 * * * runs every minute during the 9 AM hour (60 executions), not once at 9:00 AM. Use 0 9 * * * for a single run.
Forgetting that day-of-week 0 is Sunday — 0 9 * * 0 is Sunday, not Monday. Monday is 1. Some systems also accept 7 for Sunday, but 0 is universal.
Mixing day-of-month and day-of-week — 0 9 15 * 1 does NOT mean "the 15th if it falls on Monday." In most cron implementations, if both fields are set, the job runs when EITHER condition is true (the 15th OR any Monday).
Timezone confusion — cron uses the server timezone. If your server is UTC, 0 9 * * * runs at 9 AM UTC (4 AM Eastern, 1 AM Pacific). Always verify your server timezone first.

Developer Tools That Pair With Cron

Cron Expression Generator — build and validate any cron schedule
Timestamp Converter — convert between timezones when scheduling across regions
JSON Formatter — format CI/CD config files containing cron triggers
Code Formatter — clean up the shell scripts your cron jobs execute
Diff Checker — compare crontab versions before and after changes
Regex Tester — build patterns for log parsing in scheduled cleanup jobs

Need a custom schedule not on this list? Build it visually in seconds.

Open Cron Generator

Crontab Cheat Sheet — 25 Common Cron Schedules Ready to Copy

Minute Intervals

Hourly Intervals

Daily Schedules

Weekly, Monthly & Beyond

Reading Cron Expressions — Quick Decoder

Cron Shorthand (Non-Standard)

Common Mistakes

Developer Tools That Pair With Cron

Related Posts

Cron Generator Guide

Cron for Beginners

Crontab Intervals

Linux Crontab Guide