0 0 1-30/3 * *. Ten runs per month at every 3rd day-of-month starting from the 1st. The cadence resets at the month boundary; see the pillar guide for the runtime-check workaround.View future cron matches in a calendar
Showing next 1000 cron schedules
0 0 1-30/3 * *
The day-of-month range 1-30/3 expands to 1, 4, 7, 10, 13, 16, 19, 22, 25, 28 — ten runs per month. The 31st and the month boundary reset the phase, so the gap between runs occasionally shrinks to 1-2 days at the boundary. For strict 72-hour intervals, schedule daily and check `date +%j` modulo 3.
See the dedicated guide for the full breakdown: Cron every day.
Paste it into the editor above to see the next runs on a calendar.
0 9 1-30/3 * * — every 3 days at 09:000 0 2-31/3 * * — every 3 days starting from the 2nd0 0 1-30/3 * * uses standard 5-field cron syntax, so it works in:
crontab — 0 0 1-30/3 * * /path/to/script.shvercel.json.cron(...) with day-of-week as ? and a year field.0) and append day-of-week ?.`0 0 1-30/3 * *`. Paste this into any cron-compatible scheduler (Linux crontab, AWS EventBridge, Vercel cron, Quartz, node-cron, robfig/cron) to run a job every 3 days.
The editor above shows the next 30+ runs on a calendar in your local timezone, plus a plain-English description. If the calendar matches your intent, the cron is correct.
It uses standard 5-field cron syntax, so yes — Linux crontab, AWS EventBridge (with the additional `?` and year fields), Vercel cron jobs, Quartz Scheduler, node-cron, robfig/cron, and Kubernetes CronJob all accept it. Vercel's free Hobby plan caps the minimum frequency at once-per-day; the Pro plan removes that cap.
Most schedulers will start the new run anyway, leading to overlap. To prevent this, wrap the command with `flock -n /tmp/myjob.lock /path/to/script.sh` on Linux, or set `concurrencyPolicy: Forbid` on Kubernetes CronJob. Vercel cron and AWS EventBridge let you configure concurrency at the platform level.
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