Cron Expression Builder
Build and validate cron expressions visually. Get a human-readable description of your schedule and preview the next 10 run times instantly.
* = every
* = every
* = every
* = every
* = every
🏗 Visual builder
Edit each field of your cron expression separately — minute, hour, day, month, weekday — and watch the expression update live.
💬 Human readable
Instantly translates any cron expression into plain English so you can confirm your schedule does exactly what you intend.
📅 Next run preview
See the next 10 scheduled run times with exact dates and relative times like "in 3 hours" or "in 2 days".
⚡ Common presets
One-click presets for the most common schedules — every minute, hourly, daily, weekly, monthly, and more.
✓ Instant validation
Invalid expressions are caught immediately with clear error messages explaining what went wrong.
🔒 100% private
Everything runs in your browser. Your cron schedules and job names never leave your machine.
How to use the Cron Builder
Understanding the five cron fields
A standard cron expression has five fields separated by spaces: minute hour day-of-month month day-of-week. Each field accepts specific values, ranges, step values, and the wildcard *. For example, 0 9 * * 1-5 means "at 9:00 AM every weekday." Some systems like AWS and Quartz add a sixth field for seconds.
Common cron patterns
Every minute: * * * * *. Every hour at :30: 30 * * * *. Every day at midnight: 0 0 * * *. Every weekday at 9 AM: 0 9 * * 1-5. Every Sunday at 2 AM: 0 2 * * 0. First day of every month: 0 0 1 * *. Every 15 minutes: */15 * * * *.
Step values and ranges
The / operator defines steps. */5 in the minutes field means "every 5 minutes." 0-30/5 means "every 5 minutes between the 0th and 30th minute." Ranges use -: 1-5 in the day-of-week field means Monday through Friday. Lists use commas: 0,12 in the hour field means midnight and noon.
Cron in different systems
Standard Unix cron runs as the system cron daemon. Node.js uses libraries like node-cron or cron. Python uses APScheduler or the system crontab. AWS EventBridge uses a cron format with six fields including year. GitHub Actions uses standard five-field cron in workflow triggers. Kubernetes CronJobs use the same five-field format. Always check your platform's docs — some add extensions like @hourly or @reboot shortcuts.