Write or read a cron expression field by field, in Unix or Quartz flavour, and see the next runs in your own time zone or UTC before you schedule it.
How it works
Type an expression into the box or build it a field at a time in the row beneath; the two are the same string, so editing either rewrites the other. The page describes the schedule in a sentence and lists the next six runs, in UTC by default or in your own time zone.
Three flavours are covered. Unix is the five fields of a crontab line. The seconds flavour puts a seconds field in front, as Spring's @Scheduled does. Quartz takes six or seven fields, counts Sunday as 1, and adds ?, L, W and # for schedules a crontab cannot express, such as the last weekday of the month.
| Field | Values | Notes |
|---|---|---|
| Minute | 0–59 | |
| Hour | 0–23 | |
| Day of month | 1–31 | Quartz also takes L, LW, L-3 and 15W |
| Month | 1–12 or JAN–DEC | |
| Day of week | 0–7 or SUN–SAT | 0 and 7 are both Sunday; Quartz counts 1–7 from Sunday |
Each field takes *, a value, a list such as 1,15, a range such as 9-17, or a step such as */15 or 5/10. The shorthands @hourly, @daily, @weekly, @monthly and @yearly expand to the fields they stand for; @reboot has no clock, so it has no next runs.
Examples
Every quarter of an hour in working hours
*/15 9-17 * * 1-5Described as “Every 15 minutes past hours 9 through 17 on Monday through Friday”. From Thursday 10 September 2026 at 12:00 UTC the next runs are 12:15, 12:30, 12:45 and 13:00. The day's last run is 17:45, not 17:00, because the hour field matches all of hour 17.
Both day fields set
0 0 1,15 * 5Described as “At 00:00 on day-of-month 1 and 15 or Friday”. From the same Thursday the runs are Friday 11, Tuesday 15, Friday 18 and Friday 25 September. Tuesday is there for being the 15th.
The last weekday of every month, in Quartz
0 0 18 LW * ?Described as “At 18:00 on the last weekday of the month”: Wednesday 30 September, Friday 30 October, Monday 30 November and Thursday 31 December 2026. 31 October is a Saturday, so that month's run moves back to the Friday.
Common problems
The job runs on days you did not ask for
When both day fields are restricted, cron runs on days matching either one: 0 0 13 * 5 fires every Friday and every 13th, not only on Friday the 13th. When either field starts with * they combine the other way, so 0 0 */2 * 1 fires only on Mondays with an odd date. That is Vixie cron's rule, and the sentence under the expression says “or” or “and” to show which applies.
*/2 in the day of month is not every other day
A step counts from the start of its field and restarts each month, so 0 0 */2 * * fires on odd dates: 29 August, 31 August, 1 September, 3 September. After a 31-day month that is two days running.
A step larger than its field
A step never carries into the next field. */90 * * * * matches minute 0 alone and runs hourly, so it is described as “At minute 0”, exactly as 0 * * * * is. Every 90 minutes takes two lines, 0 0-21/3 * * * and 30 1-22/3 * * *, which together fire at 00:00, 01:30, 03:00, 04:30 and so on.
Quartz rejects a crontab line
Quartz wants a seconds field first and ? in the unused day field, so 0 9 * * MON-FRI becomes 0 0 9 ? * MON-FRI. Numbered weekdays shift too: 1-5 in Quartz is Sunday through Thursday. Switching flavour on the page rewrites weekdays as names, which mean the same days in both.
A 02:30 job and daylight saving
In Europe/Berlin the clock jumps from 02:00 to 03:00 on 29 March 2026, so 30 2 * * * has nothing to match that day and the runs go from 28 March to 30 March. On 25 October 02:30 happens twice and is listed once. Daemons differ: cronie and Debian's cron run a skipped job just after the jump and avoid running one twice when the clock goes back.
Frequently asked questions
Which time zone does cron use?
The machine's, or whatever the daemon is configured with, and never the zone of whoever wrote the line, which is why the page opens in UTC. Some crons read a CRON_TZ variable from the crontab, and Kubernetes CronJobs take a timeZone field.
Is Sunday 0 or 7?
Both, in a crontab. Quartz counts 1 for Sunday through 7 for Saturday, so there a 7 means Saturday. Writing SUN avoids the question in both.
What is the question mark for in Quartz?
Quartz does not support restricting the day of month and the day of week at once, so one of them must be ?, meaning no specific value. A crontab has no such rule and uses *.