Cron HelperCron expression for every minute
Every minute.
Five fields for Linux, GitHub Actions and Kubernetes (minute hour day month weekday). Six or seven for Quartz. Nothing you type leaves your device.
What it means and when to use it
Five stars is the shortest cron expression there is, and the most dangerous to leave in by accident. It means "every minute of every hour of every day". It is useful for short tests (to see that a job runs at all before you slow it down), for lightweight checks such as "is this service answering", and for queues that must be looked at constantly. Because the job starts 1,440 times a day, it must finish in well under a minute and must be safe to run twice at once.
Watch out for this
If one run takes longer than a minute, the next run starts while the first is still going, and the two can fight over the same file or database row. Guard the script with a lock (the flock command on Linux does this) or make it exit at once when another copy is running. Also remember the output: cron mails or logs whatever the job prints, so a chatty script produces a thousand messages a day. Redirect output to a file, or print only when something is wrong.
What each field says
| Field | Written | Means |
|---|---|---|
| Minute | * | every minute |
| Hour | * | every hour |
| Day of month | * | every day of the month |
| Month | * | every month |
| Day of week | * | every day of the week |
An example of the next runs
If it were Friday 13 November 2026 at 10:20 UTC, the next six runs would be these. Times are shown in UTC and in India time (UTC+5:30).
| UTC | India time |
|---|---|
| Fri 13 Nov, 10:21 | Fri 13 Nov, 15:51 |
| Fri 13 Nov, 10:22 | Fri 13 Nov, 15:52 |
| Fri 13 Nov, 10:23 | Fri 13 Nov, 15:53 |
| Fri 13 Nov, 10:24 | Fri 13 Nov, 15:54 |
| Fri 13 Nov, 10:25 | Fri 13 Nov, 15:55 |
| Fri 13 Nov, 10:26 | Fri 13 Nov, 15:56 |
The same schedule in other places
Quartz
Quartz has a seconds field in front, uses ? in one day field, and counts Sunday as 1:
0 * * * * ?GitHub Actions
GitHub documents once every 5 minutes as the shortest interval for scheduled workflows, so this schedule is too frequent there. Use */5 * * * * as the fastest.
Kubernetes CronJob
In a CronJob manifest the schedule goes in spec.schedule. Without spec.timeZone, it is read in the time zone of the cluster's controller:
spec:
schedule: "* * * * *"
timeZone: "Etc/UTC"A crontab line to copy
The command is made up. Replace it with your own and use full paths:
* * * * * /home/me/bin/check-service.sh >> /home/me/check.log 2>&1Questions
Can GitHub Actions run every minute?
No. GitHub documents the shortest interval for scheduled workflows as once every 5 minutes, so use */5 there.
Is every minute the fastest cron can go?
In standard five-field cron, yes: the smallest unit is a minute. Quartz has a seconds field, so it can run every second, which standard cron cannot.
This is an independent guide and tool. It is not connected with crontab.guru, Quartz, GitHub, Kubernetes, Spring or the Linux projects named here. Product names belong to their owners.