Cron Explainer

Read a schedule in plain English and see its next runs — Linux cron, Kubernetes, GitHub Actions, Quartz/Spring, AWS EventBridge and systemd timers.

Runs entirely in your browser. Your browser blocks this page from opening connections or loading anything from other sites. Nothing you enter is uploaded or saved.

requests since opened: 0
How to verify this yourself
  1. Open your browser’s developer tools (F12, or ⌥⌘I on Mac) → Network tab, then use the tool. No new requests appear.
  2. Or disconnect from the internet after the page loads — the tool keeps working, because it never needed the network.
  3. See the rule itself: in the Network tab, select this page’s document → Response Headers → content-security-policy contains connect-src 'none' and no 'unsafe-inline' for scripts.
  4. Press Test the lock: the page tries a harmless request and the browser blocks it (the Console shows the refusal).
How to use
  1. Pick where the schedule runs — each system reads cron differently.
  2. Paste the expression to read it in English, field by field.
  3. Check the next runs in the right time zone.

Where does this schedule run?

crontab(5): minute hour day-of-month month day-of-week

“At 09:00 on Monday through Friday.”

field by field

Minute00
Hour99
Day of month*every value
Month*every value
Day of week1-5Mon, Tue, Wed, Thu, Fri

next runs in

    Times inside a daylight-saving gap are skipped here; some schedulers run them late instead.

    Common questions

    What does */5 mean in cron?

    “Every 5th value”: in the minute field, */5 runs at minutes 0, 5, 10 and so on. A range with a step, such as 10-30/5, runs at 10, 15, 20, 25 and 30.

    Why does my cron job run on unexpected days?

    In standard cron, if both day-of-month and day-of-week are set, the job runs when either matches. The explainer warns about this.

    Which time zone does cron use?

    The scheduler’s: the server’s time zone for crontab, .spec.timeZone for Kubernetes, and always UTC for GitHub Actions and EventBridge rules.

    Known limitations

    • systemd: "~" (days from the end of the month) is not supported yet.
    • EventBridge rate() runs relative to when the rule was created, so next runs cannot be listed.
    • Times inside a daylight-saving gap are skipped; some schedulers run them late instead.
    • Browser extensions with access to this site can read the page. For sensitive data, use a private window with extensions off. How the lock works

    tools v0.9.0 · build 7317bbb · 2026-10-07

    Related reading on CipherMind

    Standards & references