Cron Generator
Cron syntax is five fields of terse punctuation that decide when your job runs at 3am. This generator lets you build the expression one field at a time, translates it back into a sentence, and shows you the next five times it would actually fire.
Runs entirely in your browser. Nothing you paste is uploaded.
Cron Expression
About the Cron Generator
The five fields are minute, hour, day of month, month, and day of week, in that order. An asterisk means every value, */5 means every fifth value, 1,15 means those two values, and 1-5 means an inclusive range.
The preview matters more than the syntax. Most cron mistakes are not typos, they are expressions that parse fine but fire far more or far less often than intended. Setting day of month and day of week together is the classic trap: cron treats them as OR, not AND, so 0 0 1 * 1 runs on the first of the month and every Monday.
Frequently asked questions
What does */5 mean in cron?
It is a step value: run every fifth unit of that field. In the minute field, */5 fires at :00, :05, :10 and so on through the hour.
Why does my job run more often than expected?
You have probably set both day of month and day of week to something other than *. Cron ORs those two fields together rather than ANDing them, so the job fires when either matches.
What timezone does cron use?
The system timezone of the machine running it, unless the scheduler supports an explicit TZ. Container schedulers usually default to UTC, which is a common source of off-by-hours surprises.