Does cron support seconds?

Standard cron uses five fields and the smallest unit is one minute. Some schedulers add a sixth seconds field, but that is an extension, not the classic format.

What does */5 mean in cron?

The slash is a step value. In the minute field, */5 means every 5 minutes: 0, 5, 10, and so on.

Does this send my data anywhere?

No. Utilumo's developer tools parse and transform input inside the browser tab. Nothing is uploaded, stored, or logged.

Guide1 min readUpdated June 25, 2026

Cron syntax explained with examples

Short answer

A standard cron expression has five fields separated by spaces: minute, hour, day of month, month, and day of week. Each field is a number, a range, a list, a step, or `*` for any value.

The five fields

* * * * *
| | | | |
| | | | +-- day of week  (0-6, Sunday = 0)
| | | +---- month         (1-12)
| | +------ day of month  (1-31)
| +-------- hour          (0-23)
+---------- minute        (0-59)

Field order and ranges

Special characters

* — any value (every minute, every hour, and so on)
, — a list, for example 1,15,30
- — a range, for example 1-5
/ — a step, for example */15 means every 15 units

Common examples

0 9 * * 1-5 — at 09:00 on weekdays
*/15 * * * * — every 15 minutes
0 0 1 * * — at midnight on the first day of each month
30 8 * * 1 — at 08:30 every Monday

Day of month and day of weekWhen both the day of month and day of week fields are restricted, most cron implementations run when either matches, not both. This surprises people writing schedules like 0 0 13 * 5.

Try it: Cron Expression BuilderBuild, validate, and read back a plain-English explanation of a cron expression locally.Open tool

Note that some schedulers extend this format. A few add a seconds field at the front or a year field at the end, so always check the documentation for the system you are targeting.