How to use it
- Type or build a cron expression.
- Read the plain-language description.
- Check the next run times.
Why use it
- Understand any cron schedule instantly.
- Avoid misconfigured jobs.
- See exactly when tasks will run.
- Build schedules field by field.
- Free and works in any browser.
How cron expressions work
Cron is a scheduling utility found on Unix-like systems. It runs commands or jobs at times you define with a compact expression. A standard cron expression has five fields, each separated by a space:
| Field | Allowed values | Example |
|---|---|---|
| Minute | 0–59 | 30 = at minute 30 |
| Hour | 0–23 | 9 = at 9 AM |
| Day of month | 1–31 | 15 = on the 15th |
| Month | 1–12 | 6 = June |
| Day of week | 0–7 (0 and 7 are Sunday) | 1 = Monday |
Special characters
- *: every value in the field (
* * * * *= every minute). - */n: every n units (
*/5in the minute field = every 5 minutes). - a-b: a range (
1-5in DoW = Monday to Friday). - a,b,c: a list (
0,6,12,18in hour = every 6 hours). - L: last day or weekday of the month.
Writing cron by hand is error-prone because a small mistake, like putting a job in the minute field when you meant the hour field, silently changes when it runs. Using a generator that shows the plain-language description and next execution times makes misconfigurations obvious instead of catching them after a job runs at the wrong time.