Cron: Every Month
0 0 1 * * runs once a month, at midnight on the 1st — the day-of-month field is pinned to 1 while month and day-of-week stay wildcarded. It's the standard pattern for monthly billing runs, archival jobs, and reports that align with calendar months.
0 0 1 * *
Examples & Variations
Common Mistakes
- Picking a day-of-month past 28 for a schedule meant to run "every month" — February doesn't have a 30th or 31st, so those runs simply never fire in short months.
- Assuming "every month" always means the 1st — some workflows actually need the last day of the month, which standard cron can't express directly (see the last-day-of-month guide).
- Forgetting that day-of-month and day-of-week are OR'd together in standard cron — setting both to non-wildcard values doesn't mean "AND," it means either condition triggers the job.
Best Practices
- For billing-cycle or calendar-month jobs, the 1st at midnight is the safest anchor point since every month has one.
- If you need quarterly instead of monthly, use the month field's step or list syntax (0 0 1 1,4,7,10 * or 0 0 1 */3 *) rather than trying to compute quarters in the day-of-month field.
- Document explicitly whether "monthly" in your system means calendar month or a rolling 30-day window — they're not the same, and cron only expresses the former.
Frequently Asked Questions
- Is 0 0 1 * * the same as @monthly?
- Yes — @monthly is a standard cron nickname that expands to 0 0 1 * *, firing at midnight on the first day of every month.
- How do I schedule a job for the 15th of every month instead?
- Change the day-of-month field: 0 0 15 * * runs at midnight on the 15th of every month.
- What happens in February when day-of-month is set to 30?
- The job simply doesn't run that month — cron checks the literal calendar date, and if it doesn't exist (Feb 30, Feb 31, Apr 31), that occurrence is silently skipped.