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Cron Expression Builder

Write it, read it back in plain English, and see when it actually fires.

Every 5 minutes.

Next runs — UTC

  1. Thu, 30 Jul 2026, 23:40
  2. Thu, 30 Jul 2026, 23:45
  3. Thu, 30 Jul 2026, 23:50
  4. Thu, 30 Jul 2026, 23:55
  5. Fri, 31 Jul 2026, 00:00

Five fields. Runs in the server's local timezone.

Cron uses the server’s timezone, which is often not yours. Check before you trust a time.

Fields

  • minute0–59
  • hour0–23
  • dom1–31
  • month1–12
  • dow0–7

About Cron Expression Builder

Type an expression and read it back in plain English, or work backwards from the schedule you want. The next five run times are calculated in the timezone you pick, because cron uses the server's timezone and that is rarely the one you are sitting in. Choose the dialect you are actually targeting — crontab, Kubernetes, GitHub Actions, Quartz and AWS EventBridge disagree about field counts, day numbering and which special characters exist, and an expression that is valid in one is rejected or silently wrong in another.

  • Five dialects, validated properly — crontab, Kubernetes, GitHub Actions, Quartz, AWS
  • Next run times in any timezone, with UTC-only dialects handled
  • Warns when day-of-month and day-of-week combine as OR rather than AND
  • Flags schedules that daylight saving skips or runs twice

How to write a cron expression

  1. 1Pick the system you are writing for — the field count and day numbering depend on it.
  2. 2Type the expression, or start from one of the common schedules.
  3. 3Read the plain-English description to check it means what you intended.
  4. 4Set your timezone and confirm the next run times look right.

Frequently asked questions

What do the five fields in a cron expression mean?
In order: minute, hour, day of month, month, day of week. Quartz adds a seconds field at the front and an optional year at the end; AWS EventBridge uses six fields ending with year.
Does 0 0 13 * 5 mean Friday the 13th?
No, and this is the most common misreading in cron. When both the day-of-month and day-of-week fields are restricted, the job runs when either matches — so that expression fires on every 13th and also on every Friday. Leave one field as * if you meant an AND.
Is 1 Monday or Sunday?
It depends on the dialect. crontab and Kubernetes count 0-6 from Sunday and also accept 7 for Sunday; Quartz and AWS count 1-7 from Sunday, so their 1 is Sunday and 2 is Monday. Writing MON or FRI avoids the question entirely.
What timezone does cron use?
The server's local timezone, unless the system sets CRON_TZ. GitHub Actions and AWS EventBridge always use UTC. That difference is why a job scheduled for 09:00 sometimes runs at what feels like the wrong time.
What happens to a cron job when the clocks change?
In a daylight-saving timezone, a job scheduled inside the transition window runs twice when clocks go back and not at all when they jump forward. 02:00 is the usual casualty. This tool flags both cases in the run preview.
Why does my expression never run?
Usually an impossible date. 0 0 30 2 * asks for 30 February, which has never existed, so cron accepts the entry and simply never fires. The preview says so explicitly rather than showing an empty list.