Cron Expression Parser

About Cron expression parser

The cron expression parser translates a five-field crontab schedule into a plain-English sentence, breaks each field down, and lists the next eight times it would fire. It understands names such as MON and JAN, ranges, lists, steps and macros like @daily. It answers the common question of whether a schedule really means what you think it does before you deploy it.

How to use it

1. Type an expression into the Cron expression field, or press a quick pick such as Every weekday. The field starts with five asterisks.
2. Read the sentence that appears beneath it, or the red error if the expression is invalid.
3. Check the Field breakdown cards for Minute, Hour, Day of month, Month and Day of week, each with its allowed range.
4. Scan Next 8 run times, and press Refresh to recalculate from the current moment.
5. Press Copy expression to keep the schedule.

The 15th of the month, or any Friday

30 2 15 * FRI (checked on Saturday 2026-09-19)

Runs at 02:30 on Fri Sep 25, Fri Oct 2, Fri Oct 9 and Thu Oct 15, 2026

When to use it

• Double-checking a backup or report schedule before adding it to a crontab.
• Decoding an unfamiliar expression inherited from an old server.
• Confirming a CI or scheduler setting fires on the days you intended.
• Teaching a teammate how ranges, lists and step values combine.

Questions about Cron expression parser

Which times are shown in the run list?

They are in your browser's local time zone. A server may run cron in UTC, so convert before assuming a job fires at the hour you see here.

Can I write MON-FRI, JAN or 7 for Sunday?

Yes. Day names, month names and both 0 and 7 for Sunday are accepted, along with ranges such as 9-17, lists such as 1,15 and steps such as */10 or 10-40/10.

How are day of month and day of week combined?

As in cronie: if neither field starts with a star, a day matches when either one does, so 30 2 15 * 5 runs on the 15th and on every Friday. If either field starts with a star, even a stepped one such as */2, both fields must match.

Are shortcuts such as @daily supported?

Yes. @yearly, @annually, @monthly, @weekly, @daily, @midnight and @hourly are expanded to their five-field form. @reboot has no schedule, so it produces an error.

Does it support a seconds field?

The description can read a six-field version, but the breakdown and run list are shown only for standard five-field expressions, so those sections stay hidden if you add seconds.

What does No matches found in the next four years mean?

The preview searches four years ahead, enough to reach February 29. A schedule such as 31 February never matches, so the list is empty.

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