Cron Expression Builder
Build and decode cron schedules locally with human-readable explanations. Your expressions never leave the browser.
At 09:00, Monday through Friday
Next runs
- *
- any value
- ,
- list, e.g. 1,15
- -
- range, e.g. 1-5
- /
- step, e.g. */10
@daily, @hourly and @weekly are also accepted.How it works
Cron expressions encode recurring schedules as five or six space-separated fields covering minutes, hours, day-of-month, month, day-of-week, and optionally seconds. This builder assembles those fields from simple controls and mirrors the classic Unix crontab syntax so the result pastes cleanly into CI systems, Kubernetes CronJobs, and cloud schedulers. A local humanization library translates the expression into plain English so you can verify intent without memorizing every special character. Common shortcuts like wildcards, ranges, lists, and step values are supported through the field editors. Because evaluation is client-side, experimental schedules for private infra never hit a remote parser. Use the preview to catch mistakes such as impossible day/month combinations before deploying. Always confirm timezone behavior in the target runtime—cron itself is timezone-agnostic and your platform may interpret fields in UTC or local time.
Frequently asked questions
Is this five-field or six-field cron?
The builder targets the common five-field Unix style (minute hour day month weekday). Adjust if your platform expects seconds.
Are schedules executed here?
No. The tool only authors expressions and previews the next run times in your local timezone. Execution happens in your own systems.
Does input get uploaded?
Never. Expression building and humanization run entirely in your browser session.
Why does my job run at the wrong hour?
Most platforms evaluate cron in UTC or a configured timezone. Align the expression with that timezone.