The closest cron expression for every 3 days is 0 0 */3 * *. It restarts on the 1st of each month, so check the real run dates here and see the one-line fix for an exact three-day rhythm.
0minute0hour*/3day*month*weekday*/3 isn't really every 3 days
The day-of-month field restarts on the 1st of every month, so the last run of a month is followed by a run on the 1st — anywhere from 1 to 3 days later depending on the month. For an exact spacing, run daily and have the command skip days.
In Plain English
What your cron expression actually means.
Upcoming Executions
Preview the next 50 times this schedule will trigger.
About 0 0 */3 * *
0 0 */3 * * runs at midnight on the 1st, 4th, 7th… of each month, and the step restarts on the 1st, so the gap across a month boundary is anywhere from one to three days. For an exact three-day rhythm, run daily and let the command act on every third Unix day; the exact crontab below does that (the backslashes stop crontab from treating % as a newline).
Cron reads the five fields as minute hour day month weekday. For this schedule that breaks down as:
| Field | Position | Matches |
|---|---|---|
0 | minute | 0 |
0 | hour | 0 |
*/3 | day of month | 1, 4, 7, 10, 13, 16, … 31 (11 values) |
* | month | every month |
* | day of week | every day of the week |
New to cron? Read the syntax reference or the FAQ.
Use it in crontab or GitHub Actions
The single line below is the closest cron gets, not the exact schedule (see above). A crontab runs in the server's local timezone; GitHub Actions always evaluates schedules in UTC. For Kubernetes, AWS EventBridge, or Vercel, use the export menu in the calculator above.
crontab
# At 12:00 AM, on day 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, and 31 of the month 0 0 */3 * * /path/to/command
GitHub Actions workflow
# At 12:00 AM, on day 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, and 31 of the month
# Note: GitHub Actions always runs schedules in UTC.
on:
schedule:
- cron: '0 0 */3 * *'Exact version for crontab
0 0 * * * [ $(expr $(date +\%s) / 86400 \% 3) -eq 0 ] && /path/to/command