Cron Expression
0 0,12 * * *
Cron Expression: Cron Twice a Day
Learn how to create a cron expression for 'cron twice a day'. Runs at midnight and noon, 12 hours apart, with our free cron generator tool.
Expression Breakdown
0
Minute(0-59)
0,12
Hour(0-23)
*
Day(1-31)
*
Month(1-12)
*
Weekday(0-6)
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | At minute 0 |
| Hour | 0,12 | At hours 0,12 |
| Day of Month | * | Any day |
| Month | * | Any month |
| Day of Week | * | Any day of the week |
This cron expression represents: cron twice a day
Cron Expression
0 0,12 * * *
What This Expression Does
Runs twice per day — at midnight (00:00) and noon (12:00) — exactly 12 hours apart. The comma in the hour field is a value list: “at hour 0 and at hour 12.”
Use Cases
Twice-daily is a sweet spot when hourly is wasteful but daily is too stale:
- Syncing product catalogs or inventory with a partner system
- Sending morning and evening notification digests
- Refreshing reporting tables ahead of both work shifts
- Checking certificate expiry or domain health twice a day
How to Use
- Copy the cron expression above
- Open your crontab with
crontab -e - Add a new line with:
0 0,12 * * * /path/to/your/script.sh - Save and exit
Picking Your Own Two Times
The list syntax takes any pair of hours: 0 6,18 * * * runs at 6am and 6pm; 30 9,21 * * * runs at 9:30am and 9:30pm. The two runs don’t need to be 12 hours apart — 0 8,17 * * * (start and end of the workday) is perfectly valid.
Alternative Formats
-
Step syntax:
0 */12 * * *— equivalent to0 0,12 * * *, since*/12selects hours 0 and 12 -
Twice a day, weekdays only:
0 0,12 * * 1-5 -
With logging:
0 0,12 * * * /path/to/script.sh >> /var/log/cron.log 2>&1