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Crontab cron expression: twice a day at 9am and 9pm
To run a Crontab job twice a day at 9am and 9pm, use:
0 9,21 * * *At minute 0, during hours 09, 21.
Your week at a glance
Upcoming runs
| # | Local | UTC | From now |
|---|
Copy-ready code
Why use this schedule
A morning and an evening run. Listing the two hours with a comma keeps the intent obvious to the next person reading the config, which matters more than saving a few characters.
- Morning and evening status reports
- Syncing inventory before and after business hours
- Refreshing a feed twice daily
First runs, as an example
Starting from 1 January 2027, evaluated in UTC:
| # | Date and time (UTC) |
|---|---|
| 1 | Fri, 01 Jan 2027, 09:00:00 |
| 2 | Fri, 01 Jan 2027, 21:00:00 |
| 3 | Sat, 02 Jan 2027, 09:00:00 |
| 4 | Sat, 02 Jan 2027, 21:00:00 |
| 5 | Sun, 03 Jan 2027, 09:00:00 |
| 6 | Sun, 03 Jan 2027, 21:00:00 |
Twice a day at 9am and 9pm in every dialect
| System | Expression |
|---|---|
| Crontab (this page) | 0 9,21 * * * |
| Quartz | 0 0 9,21 * * ? |
| Spring | 0 0 9,21 * * * |
| Kubernetes | 0 9,21 * * * |
| AWS EventBridge | 0 9,21 * * ? * |
| Jenkins | H 9,21 * * * |
| GitHub Actions | 0 9,21 * * * |
| node-cron | 0 9,21 * * * |
| Apache Airflow | 0 9,21 * * * |
| Azure Functions | 0 0 9,21 * * * |
| Google Cloud Scheduler | 0 9,21 * * * |
Need to translate a different expression? Use the cron converter.
Ready-to-use Crontab config
Drop this into your project. The expression is the one above.
0 9,21 * * * /path/to/command >> /var/log/job.log 2>&1The Crontab fields, in order: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), day-of-week (0-7, 0 and 7 = Sunday).
Things to watch out for in Crontab
- Fields are minute, hour, day-of-month, month, day-of-week. There is no seconds field, so one minute is the finest resolution.
- Cron runs in the server's local time zone. Check it with the date command, or put CRON_TZ=Asia/Kolkata above the line on cronie-based systems.
The common mistake with this schedule
Writing 9-21 means every hour from 9 to 21, not just those two. Use a comma for exactly two values.
Frequently asked questions
How do I run a Crontab job twice a day at 9am and 9pm?
Use 0 9,21 * * *. At minute 0, during hours 09, 21.
What is the twice a day at 9am and 9pm cron expression in other systems?
Quartz: 0 0 9,21 * * ?; Spring: 0 0 9,21 * * *; Kubernetes: 0 9,21 * * *. The table on this page lists every dialect.
Which time zone does Crontab use for this schedule?
Cron runs in the server's local time zone. Check it with the date command, or put CRON_TZ=Asia/Kolkata above the line on cronie-based systems.