What is a cron expression?

A cron expression is a compact schedule string of five space-separated fields: minute, hour, day of month, month, and day of week. For example, "0 14 * * 1" means "at 14:00 every Monday". Schedulers like crontab, Kubernetes CronJobs, and Quartz read these fields to decide when a job runs.

How do I read the five fields of a cron expression?

Read them left to right: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-7, where both 0 and 7 mean Sunday). An asterisk means "every value", a hyphen gives a range (1-5), a slash gives a step (*/10 = every 10), and commas list values (1,15,30).

Why does my cron job with both day-of-month and day-of-week restricted behave unexpectedly?

In standard Vixie cron, when BOTH the day-of-month and day-of-week fields are restricted (not *), the job runs when EITHER matches — a union, not an intersection. So "0 0 1 * 1" fires on the 1st of the month AND every Monday. If you need an AND, you need a scheduler with that semantics (like Quartz with the ? placeholder) or extra logic in your script.

What is the difference between 0 9 * * 1-5 and 0 9 * * MON-FRI?

Nothing — they are identical. Cron accepts English three-letter names (MON-FRI, JAN-DEC) as alternatives to numbers in the weekday and month fields. Names are case-insensitive. CronVibe translates both forms to the same schedule and shows the plain-English meaning.

How does CronVibe predict future execution times?

After parsing your expression into five field masks, CronVibe walks forward minute by minute from the next minute after now, skipping ahead intelligently (whole months, whole days, whole hours) when a field doesn't match, and collects the next five timestamps the expression would fire. It uses your local time zone, just like a system crontab would.

Does CronVibe support @daily, @hourly, and other cron shortcuts?

Yes. The @yearly, @annually, @monthly, @weekly, @daily, @midnight, and @hourly aliases are expanded to their full five-field forms before parsing, and the expansion is shown so you always know exactly what runs.

Cron Expression Generator & Explainer

Five selectors in, one schedule out — or paste an expression and read it like English.

Expression · punch tape

Next 5 executions · local time

Cron Field Cheat Sheet

the five fields, decoded

Field	Allowed values	Special characters
`minute`	0–59	, - * /
`hour`	0–23	, - * /
`day of month`	1–31	, - * / ? (L W in Quartz)
`month`	1–12 or JAN–DEC	, - * /
`day of week`	0–7 or SUN–SAT (0 and 7 = Sunday)	, - * /

AOperators in one glance

`*`	every value of the field
`5`	exactly this value
`1-5`	range: 1 through 5
`*/10`	step: every 10th value
`0,30`	list: both 0 and 30
`9-17/2`	range with step: 9, 11, 13, 15, 17

BEveryday examples

`0 9 * * 1-5`	weekdays at 09:00
`/15 * * *`	every 15 minutes
`0 2 * * 6`	Saturdays at 02:00
`0 0 1 * *`	first of every month
`30 4 1,15 * *`	1st and 15th at 04:30
`0 22 * * 1-5`	weekdays at 22:00

CThe day-of-month / day-of-week trap

Standard cron runs a job when either the day-of-month or the day-of-week matches, as long as both are restricted. 0 0 13 * 5 fires on the 13th and every Friday — not "Friday the 13th". CronVibe warns you the moment you build such an expression.

Does CronVibe run on my time zone?

Yes — execution times are computed in your browser using local time, exactly like a system crontab uses the machine's local time. The clock in the header shows what "now" means to the scheduler.

Which cron dialect does CronVibe follow?

Standard Vixie/POSIX 5-field cron, the dialect used by Linux crontab, Kubernetes CronJob schedules, and most cloud schedulers. Quartz 6/7-field expressions (with seconds and years) and @reboot are not parsed — paste the five core fields instead.

Can I use names like MON or JAN?

Yes, three-letter English names are accepted in the month and weekday fields, case-insensitive, in ranges and lists too — MON-FRI is the same as 1-5.

When you need a cron string fast and need to trust it

Sysadmins, developers, and anyone wiring scheduled jobs into a crontab, CI pipeline, or task scheduler ends up here for one reason: translating timing intent into a valid five-field cron expression without second-guessing the syntax. Instead of memorizing whether Friday is 5 or 6, you pick a preset like Daily 09:00 or Weekly Mon 00:00, then fine-tune the fields. If you are debugging someone else's crontab, paste the expression back in and decode it to plain English before touching production. The copy buttons get the string into your config file with zero transcription errors.

From blank fields to a copy-ready expression

Click 01 Build to start composing a fresh expression from scratch.
Hit a preset like Daily 09:00, Weekdays 09:30, or Monthly 1st to populate the fields instantly.
Adjust individual fields as needed, then review the human-readable description shown below.
Click Copy expression for the raw string, or Copy with description to include the English summary.
Paste an existing cron string into the 02 Decode view to verify what it actually schedules.

Find the expression for the schedule you actually need

Each entry gives the five-field expression, how many times it fires in a real year, and paste-ready blocks for crontab, a Kubernetes CronJob and GitHub Actions.

All schedules Every 5 minutes Every 15 minutes Every hour Daily at 2am Weekdays at 9am 1st of the month