Cron Generator
Build and understand cron schedule expressions. Generate cron syntax with presets, customize cron frequency for any interval, and see a human-readable description. All processing happens locally.
All processing happens locally in your browser. No files are uploaded.
* * * * *About
Cron is the standard time-based job scheduler in Unix-like operating systems. It runs commands on a repeating schedule defined by a five-field expression. Every developer encounters cron: database backups, log rotation, cache clearing, certificate renewal, and scheduled reports all depend on it. The cron daemon has been part of Unix since 1979 and remains the default scheduler on Linux, macOS, and most cloud platforms.
The five cron fields
* * * * *
│ │ │ │ │
│ │ │ │ └── day of week (0-7, 0 and 7 = Sunday)
│ │ │ └─────── month (1-12)
│ │ └──────────── day of month (1-31)
│ └───────────────── hour (0-23)
└────────────────────── minute (0-59)Cron syntax operators
| Operator | Meaning | Example |
|---|---|---|
* | Every value | * * * * * = every minute |
, | List separator | 0,30 * * * * = at minutes 0 and 30 |
- | Range | 1-5 * * * * = minutes 1 through 5 |
/ | Step values | */15 * * * * = every 15 minutes |
Common cron frequency examples
| Cron expression | Schedule |
|---|---|
* * * * * | Every minute |
0 * * * * | Every hour |
0 0 * * * | Daily at midnight |
0 0 * * 0 | Weekly at midnight Sunday |
0 0 1 * * | Monthly on the 1st |
*/5 * * * * | Every 5 minutes |
0 */2 * * * | Every 2 hours |
30 4 * * 1-5 | 4:30 AM on weekdays |
0 9 * * 1 | Every Monday at 9 AM |
Where cron expressions are used
Linux/macOS crontab: crontab -e edits your user cron jobs. System-wide jobs live at /etc/crontab and /etc/cron.d/.
GitHub Actions: on: schedule: - cron: "0 0 * * *" triggers workflows on a schedule. GitHub uses POSIX cron syntax but runs on a best-effort basis during high load.
Kubernetes CronJobs: The schedule field in a CronJob spec uses standard 5-field cron syntax. Some distributions support an optional seconds field.
Vercel Cron Jobs: Define schedules in vercel.json with standard cron syntax. Minimum frequency is once per minute on Pro plans.
How to use this tool
Click a preset button (Every minute, Hourly, Daily, etc.) to fill the fields, then customize each field individually. The human-readable description updates as you type. Click Copy to copy the cron expression. To understand an existing cron expression, type it directly into the fields and read the description. The description is generated by the same cronstrue library used in production monitoring dashboards.
FAQ
- What cron format is used?
- Standard 5-field cron (minute, hour, day of month, month, day of week). This is the most widely supported format across Unix, Linux, and cloud schedulers.
- What are the common presets?
- Every minute, hourly, daily, weekly, monthly, and yearly presets are available. Click a preset to fill the fields, then customize further.
- Is any data uploaded anywhere?
- No. The cron expression is built locally in your browser.