Developer tools
Cron expression explainer
Paste a cron schedule and get a plain-English description plus the next
few times it will run. Supports the standard five fields and shorthands like
@daily or @hourly. Everything runs in your browser - nothing is uploaded.
How it works
Paste a cron expression and the tool translates it into a plain-English sentence and lists the next times it will run. A standard cron line has five fields - minute, hour, day of month, month, and day of week - and the syntax for each (a star for every value, lists with commas, ranges with a hyphen, and steps with a slash) is easy to get wrong. This explainer reads all five and tells you exactly when the job fires.
Below the description it computes the upcoming run times by stepping forward from now, so you can sanity-check a schedule before deploying it. The common shorthands like @daily and @hourly are understood too. Everything runs in your browser, so the expression you test is never uploaded.
Example. The expression 30 9 * * 1-5 reads as "at 9:30 AM, Monday through Friday", and the next-runs list shows the coming weekday mornings. Change it to */15 * * * * and the description becomes "every 15 minutes", with the next few quarter-hour marks listed.
FAQ
What do the five cron fields mean?
In order, they are minute (0 to 59), hour (0 to 23), day of month (1 to 31), month (1 to 12), and day of week (0 to 7, where both 0 and 7 mean Sunday). A value in each position says when the job runs; a star means every value of that field. So 0 0 * * * is midnight every day.
What do the star, comma, hyphen, and slash mean?
A star matches every value of a field. A comma lists several values (1,15 = the 1st and 15th). A hyphen is an inclusive range (1-5 = one through five). A slash is a step (*/10 = every tenth value, starting from the first). They combine, so 0-30/10 means 0, 10, 20, and 30. This tool resolves all of them when describing the schedule.
How are the next run times calculated?
The tool steps forward minute by minute from the current time, checking each field against the expression, and collects the first several matches. The times shown are in your own local time zone, the same clock cron would follow on a machine set to your zone, so you can confirm a schedule lines up with when you expect it to fire.
Is anything sent to a server?
No. Parsing the expression and computing the next runs are plain logic that runs entirely in your browser. Nothing you type is uploaded, logged, or stored, and the tool works offline once the page has loaded.