Every 45 Minutes Cron Expression
Step `*/45` — fires at minute 0 and minute 45, then resets each hour.
Expression
*/45 * * * *Try it in the tester →Field Breakdown
*/45
minute
*
hour
*
day-of-month
*
month
*
day-of-week
minuteevery 45 minutes, starting at 0
hourevery hour (0–23)
day-of-monthevery day (1–31)
monthevery month (1–12)
day-of-weekevery weekday (0=Sun – 6=Sat)
How It Works
Step `*/45` in the minute field matches 0 and 45 within the 0–59 range. The cadence is not a clean 45-minute interval — every hour the minute counter resets, so the gap between minute 45 of one hour and minute 0 of the next is only 15 minutes.
Example Run Times
- 12:00:00
- 12:45:00
- 13:00:00
- 13:45:00
- 14:00:00
Frequently Asked Questions
Why isn't this a true 45-minute interval?
Cron evaluates each field independently against a single time slot — it doesn't track elapsed time across boundaries. For a real 45-minute cadence, use a job scheduler with elapsed-time semantics (e.g. systemd timers with `OnUnitActiveSec=45m`) or chain `sleep 2700` inside the script.