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Crontab Cheat Sheet

A searchable reference for cron schedule syntax, named shortcuts, and common crontab expressions.

Field layout of a standard crontab line
* * * * *
| | | | |
| | | | +-- day-of-week  (0-6, Sunday is 0)
| | | +---- month        (1-12)
| | +------ day-of-month  (1-31)
| +-------- hour          (0-23)
+---------- minute        (0-59)
Expression Meaning
* * * * * The five fields in order are minute, hour, day-of-month, month, and day-of-week, followed by the command.
0-59 Minute field range: 0 to 59. This is the first field.
0-23 Hour field range: 0 to 23, where 0 is midnight. This is the second field.
1-31 Day-of-month field range: 1 to 31. This is the third field.
1-12 Month field range: 1 to 12, where 1 is January. This is the fourth field.
0-6 Day-of-week field range: 0 to 6, where 0 and 7 both mean Sunday. This is the fifth field.
* Asterisk matches every value of the field, so on its own it means every minute, hour, and so on.
1,15 A comma gives a list of specific values, here the 1st and the 15th.
1-5 A hyphen gives an inclusive range, here 1 through 5.
*/5 A slash sets a step, here every 5th value starting from the lowest, so 0, 5, 10, and onward.
0-30/10 A step applied to a range: every 10th value from 0 to 30, so 0, 10, 20, and 30.
@yearly Run once a year at midnight on January 1. Same as 0 0 1 1 *.
@annually Identical to @yearly: run once a year at midnight on January 1.
@monthly Run once a month at midnight on the first day of the month. Same as 0 0 1 * *.
@weekly Run once a week at midnight on Sunday. Same as 0 0 * * 0.
@daily Run once a day at midnight. Same as 0 0 * * *.
@midnight Identical to @daily: run once a day at midnight. Same as 0 0 * * *.
@hourly Run once an hour at the top of the hour. Same as 0 * * * *.
@reboot Run once when the cron daemon starts, usually at system boot, not on a clock schedule.
* * * * * Every minute.
*/5 * * * * Every 5 minutes.
*/10 * * * * Every 10 minutes.
*/15 * * * * Every 15 minutes.
*/30 * * * * Every 30 minutes, on the hour and at half past.
0 * * * * Every hour, at minute 0.
0 */2 * * * Every 2 hours, on the hour.
0 */6 * * * Every 6 hours, at 00:00, 06:00, 12:00, and 18:00.
0 */12 * * * Every 12 hours, at midnight and noon.
0 0 * * * Every day at midnight (00:00).
0 8 * * * 8:00 AM every day.
30 8 * * * 8:30 AM every day.
0 12 * * * Noon (12:00) every day.
0 0,12 * * * Twice a day, at midnight and noon.
0 9-17 * * * Every hour on the hour from 9:00 AM to 5:00 PM.
0 22 * * * 10:00 PM every day.
0 9 * * 1 9:00 AM every Monday.
0 9 * * 1-5 9:00 AM every weekday, Monday to Friday.
0 17 * * 5 5:00 PM every Friday.
0 0 * * 0 Midnight every Sunday.
0 0 * * 6 Midnight every Saturday.
0 0 * * 6,0 Midnight every weekend day, Saturday and Sunday.
0 0 1 * * Midnight on the first day of every month.
0 0 15 * * Midnight on the 15th of every month.
0 0 1,15 * * Midnight on the 1st and the 15th of every month.
0 0 1 */3 * Midnight on the first day of every quarter, every 3 months.
0 0 1 1 * Midnight on January 1, once a year.

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What this tool does

This is a searchable cheat sheet for standard Unix cron, the scheduler that runs commands on a fixed time table. It covers three things: the five time fields and the operators that go in them, the named shortcuts such as @daily and @reboot, and a set of ready-to-use expressions for common schedules like every 5 minutes, weekdays at 9 AM, or the first of every month. Each row shows the expression and a plain-English meaning. The whole dataset is baked into the page, so it works offline and sends nothing anywhere.

How to use it

Start typing in the Filter box. Entering weekday surfaces the Monday to Friday schedules; entering @daily jumps to that shortcut; entering */5 finds the every-5-minutes pattern and the step operator explainer. The category buttons (All, Fields and operators, Shortcuts, Common schedules) combine with the text filter, so you can, for example, pick Common schedules and type month to see only the monthly jobs. Clear the box to see everything again. Nothing is submitted and there is no result limit.

Common use cases

  • Copying a ready-made expression for a job that should run every 5 minutes, hourly, nightly, or on weekdays.
  • Decoding a cron line you found in a repo or a server crontab and want to read at a glance.
  • Remembering the field order and which operator does what before you hand-edit a crontab.
  • Looking up what a named shortcut such as @weekly or @reboot expands to.
  • Teaching or explaining cron scheduling to a teammate with concrete examples.

Common pitfalls

  • Day-of-month and day-of-week are combined with OR, not AND. If both fields are set to something other than an asterisk, the job fires when either one matches. So 0 0 13 * 5 runs on the 13th of every month and on every Friday, which is rarely what people intend.
  • Cron uses the daemon time zone. A schedule like 0 3 * * * fires at 3 AM in whatever time zone the cron daemon uses, which may not be your local time. Check the system time zone, or set an explicit one where your cron supports it, before relying on an hour.
  • There is no seconds field. Standard cron has minute resolution, so the finest schedule is once per minute. If you need sub-minute timing, reach for systemd timers, a sleep loop, or a different scheduler.
  • Cron runs with a minimal environment. The PATH and other variables in a cron job are usually much smaller than in your interactive shell, so a command that works in the terminal can fail under cron. Use absolute paths, or set the variables you need at the top of the crontab.

Frequently asked questions

What do the five fields mean?
A standard cron line has five time fields in order: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), and day-of-week (0-6, where 0 is Sunday). A sixth part is the command to run. Each field accepts a single value, a comma list, a hyphen range, a slash step, or an asterisk that matches every value.
What does */5 mean?
The slash is a step operator. Written as */5 in the minute field, it means every 5th minute starting from 0, so minutes 0, 5, 10, 15, and on through 55. You can apply a step to a range as well: 0-30/10 means every 10th value from 0 to 30.
What happens when both day-of-month and day-of-week are set?
In most cron implementations, if you set both the day-of-month and the day-of-week to something other than an asterisk, the job runs when either one matches, not both. For example 0 0 13 * 5 runs at midnight on the 13th of the month and on every Friday. This surprises people who expect the two conditions to be combined with AND.
What does @reboot do?
@reboot is a named shortcut that runs the job once when the cron daemon starts, which is usually at system boot. It does not follow a clock schedule, so it will not repeat until the next reboot. Note that not every cron implementation supports @reboot.
How do I run a job every weekday?
Use a range in the day-of-week field. The expression 0 9 * * 1-5 runs at 9:00 AM Monday through Friday. Day-of-week 1 is Monday and 5 is Friday, so 1-5 covers the standard work week and skips Saturday and Sunday.
Are seconds supported in standard cron?
No. Standard Unix cron has minute resolution, so the smallest interval you can schedule is once per minute. Some newer schedulers, such as systemd timers or certain cron forks, add a seconds field, but the classic five-field crontab format does not.
Does this cheat sheet send anything to a server?
No. The entire reference is baked into the page and all searching and filtering happens in your browser with JavaScript. Open DevTools and watch the Network tab while you type: you will see zero requests.

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