Explain any cron schedule in plain English and preview the next run times — free, fast, private.
What is a cron expression?
A cron expression is a compact line of five fields that tells the Unix cron scheduler
when to run a job: minute hour day-of-month month day-of-week. Each field can be a
single number, a list, a range, a step, or a wildcard, so a handful of characters can describe
schedules like "every 15 minutes" or "at 09:00 on weekdays".
How to use this tool
- Type or paste a 5-field cron expression into the input box above.
- Click Parse expression — or simply start typing, the result updates as you type.
- Read the plain-English description, check the per-field breakdown, and preview the next 5 run times in your local timezone.
- If the expression is invalid, the red message under the input tells you exactly which field is wrong. Use an example button as a starting point.
Special characters reference
- * (asterisk) — matches every allowed value:
* in the minute field means "every minute".
- , (comma) — combines several values into a list:
1,15 in day-of-month means the 1st and the 15th.
- - (hyphen) — an inclusive range:
1-5 in day-of-week means Monday to Friday.
- / (slash) — a step through a range:
*/15 means "every 15", and 9-17/2 means every 2 hours from 9 to 17.
Month names (JAN to DEC) and weekday names (SUN to SAT) are accepted too, in any letter case.
Common cron mistakes — and how to fix them
- Swapped minute and hour.
0 9 * * * is 09:00 daily, but 9 0 * * * is 00:09. The minute field always comes first.
- Expecting steps to start where you want.
*/15 fires at minutes 0, 15, 30, 45. For a different offset, anchor it: 5/15 expands to 5, 20, 35, 50.
- Mixing day-of-month and day-of-week. Classic Vixie cron runs the job when either restricted field matches, so
0 0 13 * 5 fires every Friday and every 13th. This parser requires all five fields to match at once (Friday the 13th only), so compare its next-runs preview with your server's behavior before deploying.
- Impossible dates.
0 0 31 2 * — the 31st of February — never fires, and the preview shows no run within the next 366 days. Pick a day that exists, such as the 28th.
- Reversed ranges.
FRI-MON is rejected because ranges cannot wrap around. Use a list instead: FRI,SAT,SUN,MON.
Pro tip: the next 5 run times are computed in your browser's local timezone, while a real crontab follows the server's timezone. If the server runs UTC and you do not, cross-check the hours before pasting the expression into production.
Frequently asked questions
What is a cron expression?
A cron expression is a short text string of five fields (minute, hour, day of month, month, day of week) that describes a recurring schedule. The cron daemon on Unix-like systems reads these lines from a crontab file and runs the associated command whenever the current time matches all five fields.
What is the order of the five cron fields?
From left to right: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC), and day of week (0-7 or SUN-SAT). For example, '30 9 * * 1' means 09:30 every Monday.
How is the day of week numbered?
Both 0 and 7 mean Sunday, 1 is Monday, and so on up to 6 for Saturday. Three-letter names (SUN, MON, TUE, WED, THU, FRI, SAT) are accepted as well, and this tool treats them case-insensitively.
How is cron different from systemd timers?
Cron schedules jobs with a single compact line and is available on virtually every Unix-like system. Systemd timers are separate unit files that use calendar expressions, can depend on other services, log to the journal, and can catch up on runs missed while the machine was off. Cron is simpler and portable; systemd timers are more flexible on modern Linux systems.