How many times a day does */15 * * * * run?

96 times — four times per hour across 24 hours.

What is the difference between */15 and 0,15,30,45?

For the minute field they are identical. The explicit list is handy when you want a non-zero offset like 5,20,35,50.

How do I run every 15 minutes only on weekdays?

Use */15 * * * 1-5 to limit it to Monday through Friday.

Cron Expression: Every 15 Minutes

The expression is */15 * * * *. Paste it above to read it in English and see the next five run times locally. Below: how the step works and the variations people ask for.

The expression

*/15 * * * * runs a job every 15 minutes: at :00, :15, :30 and :45 past every hour, all day, every day.

Field by field

*/15 in the minute field is a step value — “every 15th minute”. The remaining * * * * leave the hour, day, month and weekday unconstrained.

Why four times an hour, not five

Steps divide the 0–59 range from zero, so */15 lands on 0, 15, 30 and 45 — four times an hour. It never fires at :60 because that is :00 of the next hour. If you actually want it aligned to a specific offset, list the minutes explicitly, e.g. 5,20,35,50 * * * *.

Common variations

Every 15 minutes during business hours: */15 9-17 * * 1-5. Every 10 minutes: */10 * * * *. Every 30 minutes: */30 * * * *.