Cron Expression Generator Guide

Common cron schedules

The schedules below answer the most searched crontab intervals in one place. Three rules apply to all of them: cron runs in the scheduler timezone (not your browser), cron jobs get a smaller environment than your shell (use absolute paths and log output), and any job that can outlive its interval needs a lock such as flock -n /tmp/job.lock.

Cron every 5 minutes — */5 * * * *

Runs at minute 0, 5, 10, 15, and so on, every hour — the standard choice for health checks, queue polling, and short cache refresh jobs. A full crontab line is */5 * * * * /path/to/script.sh; add >> /var/log/script.log 2>&1 when debugging. Standard cron has minute-level granularity, so */5 can never mean every 5 seconds. Quartz schedulers add a seconds field and write this as 0 */5 * * * ?; the 0/5 spelling is not portable across traditional crontabs.

Cron every 10 minutes — */10 * * * *

Six runs per hour at minutes 0, 10, 20, 30, 40, and 50 — a good middle ground for background sync and slower queue checks when a 5-minute schedule is too aggressive. Compare: 10 * * * * runs only once per hour, at minute 10.

Cron every 15 minutes — */15 * * * *

Quarter-hour runs at minutes 0, 15, 30, and 45, commonly used for dashboard refreshes, small batch syncs, and periodic reminders. For business-hour variants combine it with an hour range, such as */15 9-17 * * 1-5, and confirm the scheduler timezone first.

Cron every 30 minutes — */30 * * * *

Twice per hour, at minute 0 and minute 30. The classic mistake is writing 30 * * * *, which runs only once per hour at minute 30. 0,30 * * * * is an explicit equivalent in most implementations. Quartz form: 0 */30 * * * ?.

Cron every hour — 0 * * * *

Runs at minute 0 of every hour. Cron aligns to clock boundaries, so this means "at each o'clock", not "60 minutes after the job was installed". @hourly is a nickname for the same schedule where supported, but it is not universal — 0 * * * * is the portable form. Never use * * * * * for hourly jobs; that runs every minute.

Cron every day at midnight — 0 0 * * *

Once per day at 00:00 in the scheduler timezone — the usual slot for cleanup, nightly reports, and batch maintenance. If the job appears to run at the wrong local time, check the server timezone or CRON_TZ before touching the expression.

Cron every Monday — 0 0 * * 1

Weekly on Monday at midnight, for start-of-week reports and maintenance. In standard 5-field cron, 1 in the day-of-week field means Monday (0 and 7 both mean Sunday). Many parsers also accept MON, but named weekdays are not supported everywhere.

Cron every month — 0 0 1 * *

Monthly at midnight on day 1 — billing exports, monthly cleanup, summary reports. Portable cron has no last-day-of-month token: for that, run daily near midnight and let the script check whether tomorrow is the 1st. Avoid restricting day-of-month and day-of-week in the same expression unless your scheduler documents how it combines them. Quartz form: 0 0 0 1 * ?.

Linux crontab vs Quartz vs GitHub Actions vs Kubernetes CronJob

Most cron mistakes come from moving an expression between scheduler formats without checking field count, timezone, and command syntax.

Copy-ready crontab examples

Replace the script path with your real command before installing these lines with crontab -e.

Why a cron job does not run

Common errors and fixes

Edge cases table

Cron platform notes

Different schedulers use cron-like syntax with small but important differences. Treat the generated expression as a starting point, then confirm the exact field count and timezone behavior in the platform that will run the job.

Related workflow

Use the Unix timestamp converter for cron timezone checks before setting a job. Pair scheduled maintenance with the chmod calculator for scheduled maintenance scripts, or use the umask calculator for default file permissions when recurring jobs create files or directories.