Cron Expression Explainer

How to use it

Type or paste a five-field cron expression and the plain-English meaning appears as you type, along with a breakdown that explains each field on its own. Nothing is uploaded and nothing is scheduled or run — the tool only reads the expression and describes it, so it is safe to test any schedule you like. A cron expression has five fields separated by spaces, in this order: minute, hour, day of month, month, and day of week. The minute runs from 0 to 59, the hour from 0 to 23, the day of month from 1 to 31, the month from 1 to 12 (or the names jan through dec), and the day of week from 0 to 6 (or sun through sat, where both 0 and 7 mean Sunday). Reading the fields left to right tells you the exact moment or moments a job will fire. Each field accepts more than a single number. An asterisk means every value, so an asterisk in the minute field means every minute. A comma-separated list such as 1,15,30 picks out several specific values, a hyphen range such as 1-5 covers a span, and a slash step such as */5 or 9-17/2 repeats at a fixed interval. Named months and weekdays like jan and mon are accepted anywhere a number would be, which often makes an expression easier to read. As a worked example, the expression */5 * * * * runs every five minutes, 0 9 * * 1 runs at 09:00 every Monday, 0 0 1 1 * runs at midnight on the first of January, and 0 9 * * 1,3,5 runs at 09:00 on Monday, Wednesday, and Friday. The field breakdown shows how each of those pieces contributes to the overall schedule. Explaining cron this way is useful for understanding a crontab you did not write, double-checking a schedule before you deploy it, and learning the syntax without trial and error. Because the parsing happens entirely in your browser, you can paste a sensitive schedule without it leaving your device.

Frequently asked questions

What do the five fields mean?

In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12 or jan–dec), and day of week (0–6 or sun–sat, where 0 and 7 are both Sunday).

Which syntax is supported?

Asterisk (*) for every value, lists like 1,15,30, ranges like 1-5, and steps like */5 or 9-17/2. Named months (jan…dec) and weekdays (sun…sat) work too.

Does it run my cron job?

No. It only explains the schedule. Parsing happens entirely in your browser; nothing is uploaded or executed.

What does the slash in */5 mean?

The slash sets a step, or interval. In the minute field, */5 means every fifth minute — 0, 5, 10, and so on — while 9-17/2 means every second hour between 9 and 17. It is a shorthand for repeating at a fixed interval instead of listing every value by hand.