What is a cron expression and how does it work?

A cron expression is a string of 5-7 fields that defines a schedule for automated tasks. It's used by cron, a time-based job scheduler in Unix/Linux systems. Each field represents: minute, hour, day of month, month, day of week. Cron runs commands at the specified times automatically.

How do I create a cron expression online?

Use the visual builder to select time intervals, or choose from 30+ presets organized by frequency (every minute, hourly, daily, weekly, monthly). The tool shows the next 10 run times and generates code for Linux, Node.js, Python, Spring, GitHub Actions, Kubernetes, AWS, and Docker.

What do the five cron fields represent?

The five standard fields are: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC), and day of week (0-6 or SUN-SAT, where 0 is Sunday). Some systems add seconds (6 fields) or year (7 fields). Each field accepts values, ranges, lists, or wildcards.

What does the asterisk (*) mean in cron?

The asterisk (*) is a wildcard that matches all possible values for that field. For example, * in the hour field means "every hour", * in the day field means "every day". It's the most common way to say "any value is acceptable".

How do I specify a range of values in cron?

Use a hyphen (-) to specify a range. For example: 1-5 in the day of week field means Monday through Friday. 9-17 in the hour field means 9 AM to 5 PM. 1-15 in the day of month means the first half of the month.

How do I specify multiple specific values in cron?

Use commas to separate multiple values. For example: 1,15 in the day of month field means the 1st and 15th. 0,30 in the minute field means at 0 and 30 minutes. MON,WED,FRI means Monday, Wednesday, and Friday.

What does */n (step value) mean in cron expressions?

The */n syntax means "every n units". For example: */15 in the minute field means every 15 minutes (0, 15, 30, 45). */2 in the hour field means every 2 hours. */5 in the day field means every 5 days.

How do I run a cron job at a specific time daily?

Set the minute and hour to specific values, use * for the remaining fields. Examples: "30 14 * * *" runs at 2:30 PM daily. "0 9 * * *" runs at 9:00 AM daily. "0 0 * * *" runs at midnight daily.

What is the difference between Unix cron, Quartz, and AWS cron?

Unix cron uses 5 fields (minute to day-of-week). Quartz cron (Java) uses 6-7 fields with seconds and optional year. AWS EventBridge cron uses 6 fields with year support and different syntax. This tool supports all three formats with automatic conversion.

How do I schedule a cron job for weekdays only?

Use 1-5 or MON-FRI in the day of week field. Example: "0 9 * * 1-5" runs at 9 AM Monday through Friday. "0 9 * * MON-FRI" is equivalent. For weekends only, use 0,6 or SAT,SUN.

What timezone does cron use?

Standard cron uses the system timezone where it runs. This tool shows times in your browser's local timezone. When deploying, ensure your server timezone matches your expectations. Kubernetes and AWS allow specifying timezone explicitly.

How do I set up a cron job in GitHub Actions?

Use the schedule trigger with cron syntax in your workflow YAML. Example: schedule: - cron: "0 9 * * *" runs at 9 AM UTC daily. GitHub Actions uses UTC timezone. This tool generates ready-to-use GitHub Actions workflow code.

How do I create a Kubernetes CronJob?

Kubernetes CronJobs use standard cron syntax in the spec.schedule field. Example: schedule: "*/5 * * * *" runs every 5 minutes. This tool generates complete Kubernetes CronJob YAML manifests with proper configuration.

Can I combine day of month and day of week in cron?

Yes, but be careful - the job runs when EITHER condition is met, not both (in most implementations). "0 9 15 * FRI" runs on the 15th AND every Friday, not just Friday the 15th. For AND logic, add conditional checks in your script.

Is my cron expression data secure when using this tool?

Yes! All cron expression generation and validation happens 100% in your browser. Your schedules and configurations are NEVER sent to any server, stored, or logged. The tool works completely offline for maximum privacy.

What is a cron expression and how does it work?

A cron expression is a string of 5-7 fields that defines a schedule for automated tasks. It's used by cron, a time-based job scheduler in Unix/Linux systems. Each field represents: minute, hour, day of month, month, day of week. Cron runs commands at the specified times automatically.

How do I create a cron expression online?

Use the visual builder to select time intervals, or choose from 30+ presets organized by frequency (every minute, hourly, daily, weekly, monthly). The tool shows the next 10 run times and generates code for Linux, Node.js, Python, Spring, GitHub Actions, Kubernetes, AWS, and Docker.

What do the five cron fields represent?

The five standard fields are: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC), and day of week (0-6 or SUN-SAT, where 0 is Sunday). Some systems add seconds (6 fields) or year (7 fields). Each field accepts values, ranges, lists, or wildcards.

What does the asterisk (*) mean in cron?

The asterisk (*) is a wildcard that matches all possible values for that field. For example, * in the hour field means "every hour", * in the day field means "every day". It's the most common way to say "any value is acceptable".

How do I specify a range of values in cron?

Use a hyphen (-) to specify a range. For example: 1-5 in the day of week field means Monday through Friday. 9-17 in the hour field means 9 AM to 5 PM. 1-15 in the day of month means the first half of the month.

How do I specify multiple specific values in cron?

Use commas to separate multiple values. For example: 1,15 in the day of month field means the 1st and 15th. 0,30 in the minute field means at 0 and 30 minutes. MON,WED,FRI means Monday, Wednesday, and Friday.

What does */n (step value) mean in cron expressions?

The */n syntax means "every n units". For example: */15 in the minute field means every 15 minutes (0, 15, 30, 45). */2 in the hour field means every 2 hours. */5 in the day field means every 5 days.

How do I run a cron job at a specific time daily?

Set the minute and hour to specific values, use * for the remaining fields. Examples: "30 14 * * *" runs at 2:30 PM daily. "0 9 * * *" runs at 9:00 AM daily. "0 0 * * *" runs at midnight daily.

What is the difference between Unix cron, Quartz, and AWS cron?

Unix cron uses 5 fields (minute to day-of-week). Quartz cron (Java) uses 6-7 fields with seconds and optional year. AWS EventBridge cron uses 6 fields with year support and different syntax. This tool supports all three formats with automatic conversion.

How do I schedule a cron job for weekdays only?

Use 1-5 or MON-FRI in the day of week field. Example: "0 9 * * 1-5" runs at 9 AM Monday through Friday. "0 9 * * MON-FRI" is equivalent. For weekends only, use 0,6 or SAT,SUN.

What timezone does cron use?

Standard cron uses the system timezone where it runs. This tool shows times in your browser's local timezone. When deploying, ensure your server timezone matches your expectations. Kubernetes and AWS allow specifying timezone explicitly.

How do I set up a cron job in GitHub Actions?

Use the schedule trigger with cron syntax in your workflow YAML. Example: schedule: - cron: "0 9 * * *" runs at 9 AM UTC daily. GitHub Actions uses UTC timezone. This tool generates ready-to-use GitHub Actions workflow code.

How do I create a Kubernetes CronJob?

Kubernetes CronJobs use standard cron syntax in the spec.schedule field. Example: schedule: "*/5 * * * *" runs every 5 minutes. This tool generates complete Kubernetes CronJob YAML manifests with proper configuration.

Can I combine day of month and day of week in cron?

Yes, but be careful - the job runs when EITHER condition is met, not both (in most implementations). "0 9 15 * FRI" runs on the 15th AND every Friday, not just Friday the 15th. For AND logic, add conditional checks in your script.

Is my cron expression data secure when using this tool?

Yes! All cron expression generation and validation happens 100% in your browser. Your schedules and configurations are NEVER sent to any server, stored, or logged. The tool works completely offline for maximum privacy.

Cron Expression Generator

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Build and validate cron expressions with visual builder, multiple formats (Unix, Quartz, AWS), code snippets for 9 platforms, and next run time preview.

Web Developmentcronschedulercrontabschedule

100% Private - Runs Locally

How to Use

1Choose cron format (Unix, Quartz, AWS)
2Use visual builder or manual entry
3Select from 30+ presets organized by frequency
4View field breakdown and next 10 run times
5Generate code for Linux, Node.js, Python, Spring, GitHub Actions, Kubernetes, AWS, Docker

Examples

Daily Backup at Midnight

Input

Every day at 00:00

Output

0 0 * * *
Runs: Every day at 12:00 AM

Weekday Morning Report

Input

Monday through Friday at 9:00 AM

Output

0 9 * * 1-5
Runs: At 9:00 AM on weekdays

Monthly Cleanup

Input

First day of every month at 3:00 AM

Output

0 3 1 * *
Runs: At 3:00 AM on the 1st of each month

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