What is a cron expression and how do I read it?

A cron expression is a string of five fields separated by spaces that tells a scheduler when to run a task. 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 is Sunday). An asterisk (*) means 'every value,' a slash (/) means 'every Nth value,' a comma separates lists, and a dash defines ranges. For example, '30 9 * * 1-5' means 'at 9:30 AM, Monday through Friday.'

How do I schedule a cron job to run at a specific interval?

Use the step syntax with a slash (/). To run every 5 minutes, use '*/5 * * * *'. To run every 2 hours, use '0 */2 * * *'. The number after the slash is the interval. You can also combine this with ranges: '*/10 9-17 * * 1-5' runs every 10 minutes during business hours on weekdays. This visual builder lets you pick intervals from dropdowns without memorizing the syntax.

What is the difference between crontab guru and a cron parser?

A crontab guru or cron builder helps you create a cron expression from scratch using a visual interface. You select the schedule you want and it generates the expression. A cron parser does the opposite: you give it an existing cron expression and it explains what it means in plain English. Use this crontab guru to build new schedules, and a cron parser to understand existing ones. DevToolbox offers both tools.

Crontab Guru

Visual cron schedule builder. Click each field to customize your cron expression, or choose a preset. See a human-readable description and next execution times instantly.

Minute *

Hour *

Day (Month) *

Month *

Day (Week) *

* * * * *

Schedule Description

Every minute

Minute (0-59)

Runs at every minute. The field will be set to *.

Every minutes

From minute to minute

Hour (0-23)

Runs at every hour. The field will be set to *.

Every hours

From hour to hour

Day of Month (1-31)

Runs on every day of the month. The field will be set to *.

Every days

From day to day

Month (1-12)

Runs every month. The field will be set to *.

From to

Day of Week (0-6)

Runs every day of the week. The field will be set to *.

From to

Quick Presets

Next 10 Execution Times

Cron Expression Syntax Reference

A cron expression consists of five fields separated by spaces. Each field specifies when a scheduled task should execute. Cron is used in Unix/Linux crontab files, CI/CD pipelines (GitHub Actions, GitLab CI), Kubernetes CronJobs, AWS EventBridge, and cloud functions. This visual builder helps you construct valid cron expressions without memorizing the syntax.

Field Reference

Field	Allowed Values	Special Characters	Example
Minute	`0-59`	`* , - /`	`*/5` = every 5 min
Hour	`0-23`	`* , - /`	`9-17` = 9 AM to 5 PM
Day of Month	`1-31`	`* , - /`	`1,15` = 1st and 15th
Month	`1-12` or `JAN-DEC`	`* , - /`	`1-6` = Jan to Jun
Day of Week	`0-7` (0,7 = Sun) or `SUN-SAT`	`* , - /`	`1-5` = Mon to Fri

Special Characters

Character	Meaning	Example
`*`	Any / every value	`* * * * *` = every minute
`,`	Value list separator	`0 8,12,17 * * *` = 8 AM, noon, 5 PM
`-`	Range of values	`0 9-17 * * *` = every hour 9 AM to 5 PM
`/`	Step / interval	`/15 * * *` = every 15 minutes

Crontab Shorthand Strings

Shorthand	Equivalent	Meaning
`@yearly`	`0 0 1 1 *`	Once a year, Jan 1 at midnight
`@monthly`	`0 0 1 * *`	Once a month, 1st at midnight
`@weekly`	`0 0 * * 0`	Once a week, Sunday at midnight
`@daily`	`0 0 * * *`	Once a day at midnight
`@hourly`	`0 * * * *`	Once an hour, at minute 0
`@reboot`	N/A	Run once at startup

Crontab Guru

Minute (0-59)

Hour (0-23)

Day of Month (1-31)

Month (1-12)

Day of Week (0-6)

Cron Expression Syntax Reference

Field Reference

Special Characters

Crontab Shorthand Strings

Related Tools

Cron Expression Parser

Crontab Generator

Timestamp Converter

Frequently Asked Questions