Cron Every 5 Minutes

*/5 * * * *

Every hour at 00, 05, 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55 minutes past

Field by Field

Field	Value	Matches
Minute	*/5	0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
Hour	*	every hour
Day of month	*	every day
Month	*	every month
Day of week	*	every day

Why */5 and Not 0,5,10,…

Both work and both expand to the same twelve values. The step form is shorter and less error-prone, but only because 5 divides 60 evenly. */7 does not give you an every-7-minute job — it fires at 0, 7, 14, 21, 28, 35, 42, 49, 56 and then jumps back to 0, leaving a 4-minute gap every hour.

Step	Fires at	Even?
*/5	0, 5, 10 … 55	Yes
*/10	0, 10, 20 … 50	Yes
*/15	0, 15, 30, 45	Yes
*/7	0, 7, 14 … 56	No — 4-minute gap at the hour

At This Frequency, Overlap Is Certain

A job that occasionally takes six minutes will eventually have two copies running. Use a lock file, a database advisory lock or your scheduler's concurrency setting — do not assume the previous run finished.

Time Zones

Standard crontab evaluates in system local time. Vercel Cron, GitHub Actions, Kubernetes CronJobs and AWS EventBridge all evaluate in UTC. If converting your local time crosses midnight, the day-of-week field shifts too — weekdays at 5pm in UTC-07:00 is 0 0 * * 2-6, not 0 0 * * 1-5.

The Day-Field Trap

When both the day-of-month and day-of-week fields are restricted, cron matches either, not both. 0 0 13 * 5 runs on every 13th *and* every Friday — not Friday the 13th. Leave one of them as * unless you genuinely want the union.

Other Common Schedules

Expression	Runs
* * * * *	Every minute
*/5 * * * *	Every 5 minutes
*/15 * * * *	Every 15 minutes
0 * * * *	Every hour, on the hour
0 0 * * *	Every day at midnight
0 9 * * *	Every day at 9am
0 9 * * 1-5	Weekdays at 9am
0 9 * * 1	Every Monday at 9am

Making the Job Safe

• Assume double firing. DST transitions, restarts and retries all cause it. Make the job

idempotent rather than assuming exactly-once.

• Assume overlap. Cron starts the next run whether or not the last one finished. Take a

lock.

• Avoid :00. Every hourly job on the internet fires at the top of the hour; a random

minute spreads load on shared APIs.

• Log the start and end. A cron job that silently stops running is invisible until

someone notices the missing output.