How to read a cron expression
- Paste a cron expression such as
*/15 9-17 * * 1-5into the box, or click one of the common schedules. - The tool explains it in plain English and lists the next eight times it will run in your own time zone.
- To create a schedule instead, use Build a schedule: choose how often, the time and the days, and the expression is written for you.
- Copy the expression into your crontab, GitHub Actions workflow, Kubernetes CronJob or scheduler.
Cron syntax in brief
A standard cron expression has five fields: minute (0–59), hour (0–23), day of month (1–31), month (1–12 or JAN–DEC) and day of week (0–7 or SUN–SAT, where both 0 and 7 mean Sunday). Each field accepts:
*for every value,5for one value,1,15for a list and9-17for a range;*/10for every tenth value, or0-30/5for every fifth value within a range;- macros such as
@hourly,@daily,@weekly,@monthlyand@yearly.
A frequent surprise: when both day of month and day of week are set, cron runs when either matches. 0 0 13 * 5 runs on every 13th and on every Friday, not only on Friday the 13th.
Cron runs in the server's time zone, which is often UTC. GitHub Actions schedules always use UTC. The next-run list here uses your browser's time zone, so adjust if your server differs.
How do I run a cron job every 5 minutes?
Use */5 * * * *. The */5 in the minute field means every minute divisible by 5.
What does 0 0 * * 0 mean?
At midnight (00:00) every Sunday. It is the same as the @weekly macro.
Does this support seconds or Quartz syntax?
It checks standard 5-field Unix cron as used by crontab, GitHub Actions and Kubernetes. Quartz-style expressions with a seconds field or L, W and # are reported with a clear message.
Why did my job not run?
Common causes are the server using UTC, a missing newline at the end of the crontab file, relative paths, and environment variables that are set in your shell but not in cron.