A cron job is a scheduled task that runs automatically at specified times or intervals on Unix/Linux systems. The schedule is defined using a cron expression — a compact string of 5 (or 6) fields that specify the minute, hour, day, month, and day of week when the task should execute.

What does */ mean in cron?

*/n means "every n units". For example, */15 in the minutes field means "every 15 minutes", and */2 in the hours field means "every 2 hours". The * selects all values, and /n divides them into a step interval.

What is the difference between 5-field and 6-field cron?

Standard cron uses 5 fields: minute, hour, day-of-month, month, day-of-week. Extended 6-field cron (used by AWS EventBridge, Quartz Scheduler, and Spring) adds a seconds field at the beginning, making it: second, minute, hour, day-of-month, month, day-of-week. Toggle the "6-field" switch to handle both formats.

What does L mean in a cron expression?

L stands for "Last". In the day-of-month field, L means the last day of the month (e.g. the 31st in January). In the day-of-week field, 5L means the last Friday of the month. It is supported in Quartz and AWS cron but not standard Unix cron.

What does W mean in cron?

W stands for "Nearest Weekday". For example, 15W in the day-of-month field means "the nearest weekday (Mon–Fri) to the 15th of the month". If the 15th falls on a Saturday, the job runs on Friday the 14th.

How do I run a cron job every weekday?

Use 1-5 in the day-of-week field. For example, 0 9 * * 1-5 runs at 9:00 AM every Monday through Friday. You can also write MON-FRI instead of 1-5 — both are equivalent.

Can I specify multiple values in one field?

Yes. Use a comma to list specific values (e.g. 0,30 in the minutes field means "at minute 0 and minute 30"), and a hyphen for a range (e.g. 9-17 in the hours field means "between 9 AM and 5 PM"). You can combine them: 0,30 9-17 * * 1-5.

Does this tool send my cron expression to any server?

No. All parsing, explaining, and execution time calculation happens entirely in your browser using JavaScript. Your data never leaves your device.

Cron Expression Explainer

Explain cron expressions in plain English with next run times

Updated Mar 2026100% Private — runs in browser

Cron Expression Explainer

Decode cron schedules in plain English & preview next run times

Cron Expression

Fields:

MIN

HOUR

DOM

MON

1-5

DOW

Plain English

at 9:00 AM, Monday through Friday

MIN:0→at minute 0

HOUR:9→at 9:00 AM

DOM:*→every day

MON:*→every month

DOW:1-5→Monday through Friday

Next 5 Run Times

Friday, March 27, 2026 at 9:00 AMin 13h 22m
Monday, March 30, 2026 at 9:00 AMin 3 days
Tuesday, March 31, 2026 at 9:00 AMin 4 days
Wednesday, April 1, 2026 at 9:00 AMin 5 days
Thursday, April 2, 2026 at 9:00 AMin 6 days

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