Cron Expression for Every 15 Minutes
The cron expression for every 15 minutes is */15 * * * *. It runs on the quarter hour — :00, :15, :30 and :45 — which works out to four runs an hour and 96 a day.
Every 15 minutes.
*/15 * * * *Standard 5-field crontab syntax. Day of month and day of week are OR'd when both are set.
What it does
Read it field by field: minute */15, then * for hour, day of month, month and day of week. In the minute field, * stands for 0–59 and /15 means “every fifteenth value from the start of that range”, leaving 0, 15, 30 and 45. Because the other four fields are unrestricted, those four minutes match in every hour of every day.
Quarter-hour schedules are common for health checks, cache warmers, and polling a queue or inbox that needs near-real-time freshness without hammering an API. They also match how people talk about time: a report that refreshes “every quarter hour” is easy to reason about, and 96 runs a day keeps logs and API quotas manageable.
Because the runs land on round clock times, a lot of unrelated jobs across the internet also fire at :00, :15, :30 and :45. If you're calling a shared third-party API, shifting yours by a few minutes — 3-59/15 * * * * — avoids arriving in the same second as everyone else and makes rate-limit errors less likely. It costs nothing in freshness: the data is still never more than 15 minutes old.
How */15 * * * * works, field by field
| FIELD | VALUE | MEANING |
|---|---|---|
| Minute | */15 | every 15 minutes (0, 15, 30 and 45) |
| Hour | * | every hour |
| Day of month | * | every day of the month |
| Month | * | every month |
| Day of week | * | every day of the week |
Put together, cron reads */15 * * * * as: “Every 15 minutes.”
To see further ahead, paste the expression into the cron calculator, which lists the next ten run times and counts how many times the schedule runs in a year.
Frequently asked questions
How do I run a job every 15 minutes?
Add */15 * * * * /path/to/command to your crontab with crontab -e. Use an absolute path for the command, because cron runs with a minimal PATH and won't find programs your shell normally would.
How do I run every 15 minutes only during business hours?
Restrict the hour and day of week fields: */15 9-17 * * 1-5 runs from 9:00 to 17:45, Monday to Friday. The hours are in the server's timezone, so check that matches your office's.
Is */15 the same as 0,15,30,45?
Yes. Cron expands */15 in the minute field to the list 0, 15, 30, 45, so the two expressions produce identical schedules.