What */1 * * * * does
The */1 in the minute field is a step value. It means 'starting at minute 0, then every minute'. The four remaining asterisks mean every hour, every day of the month, every month and every day of the week — so the job runs continuously, all year.
Within any given hour it fires at :00, :01, :02, :03, :04, :05 ..., giving 60 runs per hour and 1440 per day.
The mistake people make
Dropping the */ changes the meaning completely. 1 * * * * runs once an hour, at minute 1 — not every minute. The slash is what turns a value into an interval.
Running every minute is almost never the right answer. It gives you 1,440 executions a day and any job that takes longer than 60 seconds will overlap with itself unless you add a lock file. Consider */5 and a queue instead.
Frequently asked questions
What is the cron expression for every minute?
*/1 * * * *. The */1 step in the minute field fires the job every minute, starting at minute 0 of each hour.
How many times does */1 * * * * run per day?
1440 times — 60 per hour, 24 hours a day.
Related cron expressions
Browse the full cron expression reference, or build your own expression from scratch.