Curated cron expression
Twice Monthly on 1st and 15th: 0 9 1,15 * *
0 9 1,15 * * — semi-monthly schedule at nine AM on two days.
Meaning at a glance
0 9 1,15 * *
Run on the 1st and 15th at 09:00
Twice monthly at 09:00 on days 1 and 15.
Next-run example: On Jan 16, next run is Feb 1 09:00.
How 0 9 1,15 * * works
Day list 1,15 creates two runs per month.
Semi-monthly billing and payroll patterns.
Preview next runs and platform conversions in CronWizard before deploying to production.
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | Configured as 0 |
| Hour | 9 | Configured as 9 |
| Day of month | 1,15 | Configured as 1,15 |
| Month | * | Every value |
| Day of week | * | Every value |
Good use cases
- Semi-monthly payroll
- Split billing cycles
- Bi-monthly reports
Timezone and daylight-saving behavior
Anchor timezone for '9 AM'.
Preview both anchors around DST.
The expression does not contain a timezone. The scheduler supplies that context. Use the next-run preview above in the same IANA timezone as production, then confirm the target platform's own timezone rules.
Platform compatibility and converted expressions
The source expression is five-field Unix cron. Use the exact equivalent below rather than adding or removing fields by sight.
| Platform | Status | Expression | What to know |
|---|---|---|---|
| Unix crontab | Ready | 0 9 1,15 * * | Use directly in a normal five-field user crontab. |
| Kubernetes CronJob | Ready | 0 9 1,15 * * | Use as spec.schedule; set spec.timeZone when local wall-clock behavior matters. |
| GitHub Actions | Ready | 0 9 1,15 * * | Use under on.schedule; UTC is the default and an IANA timezone may be specified. |
| Vercel Cron Jobs | Plan / behavior limit | 0 9 1,15 * * | The expression is valid, but Vercel always uses UTC and Hobby schedules run at most once per day. |
| AWS EventBridge Scheduler | Convert | cron(0 9 1,15 * ? *) | Convert to AWS minute-first cron(...), add the required year, and use ? in one day field. |
| Spring @Scheduled | Convert | 0 0 9 1,15 * * | Use Spring’s six fields by prepending seconds and set zone explicitly when needed. |
| systemd timer | Convert | 0 9 1,15 * * | Use OnCalendar syntax and validate it with systemd-analyze calendar on the target host. |
Edge cases to check before deployment
- Short months still have day 15.
Frequently asked questions
What does the cron expression 0 9 1,15 * * mean?
0 9 1,15 * * means “run on the 1st and 15th at 09:00.” Twice monthly at 09:00 on days 1 and 15.
What are the next run times for 0 9 1,15 * *?
On Jan 16, next run is Feb 1 09:00. Exact timestamps depend on the scheduler timezone and the current time.
What timezone does 0 9 1,15 * * use?
Anchor timezone for '9 AM'.
Can I use 0 9 1,15 * * on every scheduling platform?
No. It is a five-field Unix expression. Some platforms accept it directly, while AWS EventBridge Scheduler, Spring, and systemd require the converted form shown in the compatibility table.