★ Cron cheat sheet
Cron Expression: Every 30 Minutes During Business Hours
Twice an hour from 09:00 to 17:30, Monday to Friday. A good fit for syncing CRMs or sending queued notifications while people are working.
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The expression
*/30 9-17 * * 1-5
Every 30 minutes, during every hour from 9 through 17 on Monday through Friday.
- */30Minute
- 9-17Hour
- *Day of month
- *Month
- 1-5Day of week
✓ Valid 5-field cron
Quick picks
Typing by hand. Pick a pattern above to build one with inputs instead.
In plain English
Every 30 minutes, during every hour from 9 through 17 on Monday through Friday.
Next 10 runs
Paste it into your platform
Time zone: UTC
*/30 9-17 * * 1-5 /usr/local/bin/my-job >> /var/log/my-job.log 2>&1
- OKRuns in the server’s local time zone. cronie (RHEL, Fedora) accepts a CRON_TZ= line above the job; Debian’s cron does not.
- Heads-upEscape % as \% in the command: an unescaped % ends the command and starts stdin.
- Heads-upcron runs with a minimal PATH and no login shell. Use absolute paths and redirect output, or failures disappear.
- Linux crontab docs ↗
Cron jobs failing silently?
I build background job systems with retries, alerting and dashboards, so you hear about failures before your customers do.
What */30 9-17 * * 1-5 means
Field by field:
| Field | Value | Matches |
|---|---|---|
| Minute | */30 | 0, 30 |
| Hour | 9-17 | 9, 10, 11, 12, 13, 14 … 17 (9 values) |
| Day of month | * | any |
| Month | * | any |
| Day of week | 1-5 | Monday, Tuesday, Wednesday, Thursday, Friday |
Gotchas
- Because the hour field is 9-17, the last run is at 17:30, not 17:00. Use 9-16 plus a separate 0 17 * * 1-5 line to stop at 5pm exactly.
- Too frequent for Vercel Hobby; fine on GitHub Actions.
Does it run everywhere?
Checked against each platform's rules, assuming UTC:
| Platform | Verdict | Why |
|---|---|---|
| Linux crontab | Works, with a catch | Escape % as \% in the command: an unescaped % ends the command and starts stdin. |
| GitHub Actions | Works, with a catch | Runs at minute 0 are the most likely to be delayed or dropped under load. GitHub suggests another minute, e.g. 17. |
| Vercel | Not supported | Hobby plan: deploy fails, because Hobby cron jobs may run at most once per day. Pro and Enterprise allow once per minute. |
| AWS EventBridge | Works | Six fields: the year is added at the end, and one of day-of-month / day-of-week must be ?. |
| Kubernetes | Works, with a catch | Without timeZone, the schedule uses the kube-controller-manager’s local zone. TZ= or CRON_TZ= inside schedule is rejected from v1.29. |
Questions engineers actually ask
What is the cron for every 30 minutes during work hours?
Why does it run at 17:30?
Why does my job run on days I didn't expect?
What time zone does cron use?
Other schedules
- Every Minute
* * * * * - Every 2 Minutes
*/2 * * * * - Every 5 Minutes
*/5 * * * * - Every 10 Minutes
*/10 * * * * - Every 15 Minutes
*/15 * * * * - Every 30 Minutes
*/30 * * * * - Every Hour
0 * * * * - Every 2 Hours
0 */2 * * * - Every 3 Hours
0 */3 * * * - Every 6 Hours
0 */6 * * * - Every 12 Hours
0 */12 * * * - Twice a Day
0 9,21 * * * - Every Day at Midnight
0 0 * * * - Every Day at 9am
0 9 * * * - Every Day at Noon
0 12 * * * - Every Weekday
0 0 * * 1-5 - Every Weekday at 9am
0 9 * * 1-5 - Every Weekend
0 0 * * 6,0 - Every Monday
0 0 * * 1 - Every Friday at 5pm
0 17 * * 5 - Every Sunday at Midnight
0 0 * * 0 - Every Week
0 0 * * 0 - Every 15th of the Month
0 0 15 * * - First Day of the Month
0 0 1 * * - Last Day of the Month
0 0 28-31 * * - Every Month
0 0 1 * * - Every Quarter
0 0 1 1,4,7,10 * - Every Year
0 0 1 1 * - Every Hour During Business Hours
0 9-17 * * 1-5
Or build your own in the cron expression builder.
More from the workbench
Fine print
Tools: on the house.
Engineer: by the hour.
Infra that doesn't page you at 3am costs a little more. I build background job systems with retries, alerting and dashboards.
I'm Himanshu, an AI and full-stack engineer. I build MVPs, AI agents and the growth plumbing around them for early-stage startups.