Cron Every 45 Minutes
Set up a cron job that runs every 45 minutes using */45 * * * *. Detailed field breakdown, execution times, and practical scheduling guidance.
Cron Expression
*/45 * * * *
Field Breakdown
| Field | Value | Meaning |
|---|---|---|
| Minute | */45 | Every 45th minute |
| Hour | * | Every hour (0–23) |
| Day of Month | * | Every day of the month (1–31) |
| Month | * | Every month (1–12) |
| Day of Week | * | Every day of the week (Sun–Sat) |
Detailed Explanation
The cron expression */45 * * * * schedules a task to run at minutes that are divisible by 45 within each hour, every day of the year.
Field-by-field breakdown:
*/45(Minute): Every 45th minute, starting from minute 0. The step value/45triggers execution at minutes 0 and 45 within each hour.*(Hour): Every hour from 0 through 23. No restriction on which hour the task runs.*(Day of Month): Every day from 1 through 31. No restriction on the day of the month.*(Month): Every month from January through December. No restriction on which month.*(Day of Week): Every day of the week from Sunday through Saturday. No restriction on the day of the week.
Important note: Because */45 means "every minute where minute mod 45 equals 0," it fires at minute 0 and minute 45 of each hour. This results in two executions per hour with uneven spacing: 45 minutes between the first and second run, then only 15 minutes between the second run and the next hour's first run. If you need a true 45-minute interval, you would need a more complex approach or an external scheduler. Despite this quirk, the expression is commonly used and provides approximately 48 executions per day. This expression is supported by standard cron on Linux/macOS, as well as cloud services like AWS CloudWatch, Google Cloud Scheduler, and GitHub Actions.
Use Case
Useful for periodic cache warming tasks where you want roughly sub-hourly frequency but do not need exact 45-minute intervals between runs.
Try It — Interactive Builder
Every 45 minutes
Next 10 Executions
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