Cron Expression Explainer

Explain any Linux or Spring cron expression in plain English, field by field.

How to use the Cron Expression Explainer

1. Paste a cron expression, or pick one from Examples.
2. The dialect is detected from the number of fields: five for Linux cron, six (starting with seconds) for Spring. Choose Linux or Spring to override it.
3. Read the plain-English meaning, what each field does, and the next run times in any time zone.
4. Copy the same schedule written for the other dialect, when one exists.

Reading a cron expression

Linux cron: minute hour day-of-month month day-of-week. Spring adds second in front. In each field:

• * every value, 5 one value, 1-5 a range, 1,15 a list
• */15 every 15th value; Spring also allows 5/15, "from 5, every 15"
• Sunday is 0 or 7, and names like MON and JAN are allowed
• Spring only: ? (no specific day), L (last), W (nearest weekday), FRI#2 (second Friday)

Linux cron vs Spring: the differences that bite

• Seconds. Spring has a seconds field, so 0 */5 * * * * is every 5 minutes in Spring, while */5 * * * * is the Linux form.
• Both day fields set. Linux runs when either matches (0 9 1 * 1 is the 1st of the month and every Monday); Spring runs only when both match.
• Translation. The tool writes the equivalent in the other dialect, and explains when there's none, for example for L or a seconds value Linux can't express.

Frequently asked questions

What about Quartz and AWS expressions?

Quartz uses Spring-like fields with an optional year, but numbers weekdays 1–7 from Sunday. Remove the year and check the day of week before reading one as Spring cron.

Which time zone are the next runs in?

Your browser's zone by default. Pick the zone your server or @Scheduled(zone = …) uses; daylight saving changes are handled.

Is my expression uploaded?

No. Everything is calculated in your browser.