What is a cron expression?

A cron expression is a string of five space-separated fields that represent a schedule. The fields are: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6). For example, '0 9 * * 1-5' means 9:00 AM every weekday.

How do I validate a cron expression?

Enter your cron expression in the input field on crontab.space. The validator instantly checks the syntax and shows any errors. Valid expressions display a human-readable description and the next 5 scheduled execution times.

What does the asterisk (*) mean in cron?

The asterisk (*) in a cron expression means 'every' or 'any value'. For example, * in the minute field means every minute, and * in the day field means every day of the month.

How do I schedule a cron job to run every 5 minutes?

To run a cron job every 5 minutes, use the expression '*/5 * * * *'. The */5 in the minute field means every 5th minute, and the asterisks in other fields mean any hour, day, month, and weekday.

Can I generate a cron expression using natural language?

Yes. crontab.space features an AI-powered generator. Type your schedule in plain English like 'every Monday at 9am' or 'twice daily' and the AI generates the correct cron expression for you.

How do I run a cron job every weekday?

Use '0 9 * * 1-5' to run at 9:00 AM Monday through Friday. The 1-5 in the day-of-week field is a range covering Monday (1) to Friday (5). Change the first two fields to set a different time.

Why isn't my cron expression working?

The most common causes are: the schedule uses the server time zone (often UTC, not local time); day-of-month and day-of-week are combined with OR, not AND; standard Unix cron has no seconds field (six-field syntax is Quartz/Spring); and Sunday can be both 0 and 7. Validate the expression here to see exactly when it will run next.

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Every 15 minutes, every hour, every day

*/15 * * * *

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What does `/15 * * *` mean?

The cron expression */15 * * * * runs every 15 minutes, every hour, every day. Cron expressions have five fields — minute, hour, day of month, month, and day of week. Enter this schedule in your crontab to run a command on exactly this cadence.

Next 5 runs (UTC)

Fri, May 15, 2026, 06:15 PM

Fri, May 15, 2026, 06:30 PM

Fri, May 15, 2026, 06:45 PM

Fri, May 15, 2026, 07:00 PM

Fri, May 15, 2026, 07:15 PM

Related cron expressions

Every minute Every 5 minutes Every hour, on the hour Every 6 hours Every day at midnight Every day at 9:00 AM 9:00 AM, Monday through Friday Midnight every Sunday Midnight on the 1st of every month Every 15 min, 9 AM-5 PM, weekdays 2:30 AM every Saturday Every Monday

Every 15 minutes, every hour, every day

What does */15 * * * * mean?

Next 5 runs (UTC)

Related cron expressions

What does `/15 * * *` mean?