Cron Expression Parser
Parse cron expressions and see a human-readable explanation of when they run. Perfect for developers and system administrators who need to create or understand cron job schedules. Avoid scheduling mistakes by visualizing exactly when your cron expressions will execute.
Frequently asked questions
What is a cron expression?
A cron expression is a string of 5 or 6 fields that defines a schedule for automated tasks in Unix-like systems. The fields represent: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 are Sunday). For example, '0 9 * * 1' means 'run at 9:00 AM every Monday'.
How do I create a cron expression for a specific schedule?
Start with five asterisks (* * * * *) representing minute, hour, day, month, weekday. Replace asterisks with specific values or ranges. For example: '30 14 * * *' runs at 2:30 PM daily, '0 0 1 * *' runs at midnight on the 1st of each month, '*/15 * * * *' runs every 15 minutes. Use our parser to verify your expression does what you expect.
What does the asterisk (*) mean in cron?
An asterisk means 'every' or 'any' for that time unit. For example, * in the hour field means every hour, * in the day field means every day. So '0 * * * *' means 'at minute 0 of every hour' (hourly), while '* * * * *' means 'every minute'. It's the wildcard that matches all possible values for that field.
How do I run a cron job every 5 minutes or every N hours?
Use the step value syntax: */N. For every 5 minutes: '*/5 * * * *'. For every 3 hours: '0 */3 * * *'. The */N syntax means 'every Nth value' - so */5 in the minute field means minutes 0, 5, 10, 15, etc. You can also use ranges with steps like '0-30/5' for every 5 minutes during the first half hour.
Can I run a cron job only on weekdays?
Yes! Use 1-5 in the day of week field (the 5th field). For example, '0 9 * * 1-5' runs at 9 AM Monday through Friday. Monday is 1 and Friday is 5. You can also list specific days: '0 9 * * 1,3,5' runs at 9 AM on Monday, Wednesday, and Friday only.
What's the difference between day of month and day of week?
These are two different ways to specify which days a job runs. Day of month (3rd field) uses dates 1-31, while day of week (5th field) uses 0-7 (0 and 7 are Sunday). If both are specified (not *), the job runs when EITHER condition matches. For example, '0 0 1 * 1' runs at midnight on the 1st of every month AND every Monday.
How do I create a cron expression for business hours only?
For 9 AM to 5 PM on weekdays: '0 9-17 * * 1-5' runs at the start of each hour. For every 30 minutes during business hours: '*/30 9-17 * * 1-5'. The hour range 9-17 covers 9 AM through 5 PM, and 1-5 limits execution to Monday through Friday.
What's the difference between '0 0 * * *' and '@daily'?
They're equivalent - both run at midnight daily. Many cron implementations support special strings like @daily, @hourly, @weekly, @monthly, and @yearly as shortcuts. These are more readable but less flexible than full expressions. Use shortcuts for common intervals and full expressions for custom schedules.
Can cron expressions handle timezone differences?
Standard cron expressions run based on the server's system time. To handle timezones, either set your server's timezone correctly or calculate the time difference. Some advanced cron implementations support timezone specifications, but the basic 5-field format doesn't include timezone information.
How do I test if my cron expression is correct before deploying?
Use our Cron Expression Parser to verify your expression shows the expected schedule description. The parser explains in plain English when your job will run, helping you catch errors like '0 9 31 2 *' (February 31st doesn't exist) before deploying to production.