Cron Expression Parser

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'.

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.

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.

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.

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.

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.

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.

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.

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.