Cron Expression Parser & Next-Run Calculator
Validate a cron schedule, understand what each field means, and see the next scheduled run times in your browser's local timezone. No account or server upload is required.
Enter a cron expression
Schedule explanation
In plain English
Field-by-field breakdown
Upcoming execution times
What is a cron expression?
A cron expression is a compact schedule used by Unix-like systems and automation tools to specify when a task should run. It is commonly used for backups, scheduled scripts, maintenance jobs, reports, and recurring server tasks.
This parser supports the standard five-field cron format. Different schedulers can implement additional fields or special syntax, so always check the documentation for the system that will run your job.
Understanding the five cron fields
| Field | Allowed values | Example |
|---|---|---|
| Minute | 0–59 | */15 — every 15 minutes |
| Hour | 0–23 | 9-17 — hours 9 through 17 |
| Day of month | 1–31 | 1,15 — the 1st and 15th |
| Month | 1–12 or JAN–DEC | 1-6 — January through June |
| Day of week | 0–7 or SUN–SAT | 1-5 — Monday through Friday |
Special characters
- Asterisk (
*): every permitted value in that field. - Comma (
,): select multiple values, such as1,15. - Hyphen (
-): select an inclusive range, such as9-17. - Slash (
/): use a step, such as*/10for every ten minutes.
Important: day of month versus day of week
In standard Unix-style cron, when both the day-of-month and
day-of-week fields are restricted, the schedule normally matches
either field. For example, 0 9 1 * 1 can run at 9 AM
on the first day of a month and on Mondays. Scheduler implementations
can differ, so verify this behavior for your target system.
Does the calculator handle time zones?
Upcoming runs are shown in your browser's local timezone. Daylight saving transitions can affect local schedules, and this preview does not emulate the behavior of a particular server or scheduler. Compare the output with the timezone configured on the machine that will run your task.
Frequently asked questions
Can I enter six-field cron expressions?
No. This tool deliberately accepts the standard five-field format. Some schedulers add a seconds field or support special characters. Convert the expression to the appropriate format before using this parser.
Why is my expression valid but producing no run times?
Some syntactically valid combinations can be impossible on the calendar, such as a task scheduled for the 31st day of a month that has no 31st day. This tool searches a finite future window and reports when it cannot find the requested number of occurrences.
Does a valid expression guarantee my job will run?
No. A valid expression describes a schedule; the scheduler must still be installed, enabled, running, and configured for the correct timezone and environment.