C CalcArena

Automation control

Cron Expression Helper

Explain any cron pattern in plain English, preview upcoming executions, and export compliance-ready JSON/CSV for runbooks. Designed for SREs keeping Kubernetes, Quartz, or POSIX schedules in sync.

5 & 6-field support Natural language summary Next 5 run times Shareable URLs

Author · Pawan

Reviewer · Kushal Singh

Format: minute hour day_of_month month day_of_week [year]. Supports ranges (10-30), steps (*/5), lists (1,15), and aliases (MON, JAN).

Presets

Steps like */15 or ranges 10-30.

Use 24h format. Example: 0,12.

Use ? when relying on day-of-week.

Example: APR-JUN.

0/7=Sun, 1=Mon.

Quartz-only field.

Schedule summary

Human-readable narrative plus the next five fire times.

Live

Enter or select a cron expression to see the schedule narrative and next run list.

Implementation checklist

  1. Timezone clarity: Document whether the job runs in UTC, server local time, or a framework-specific zone.
  2. DST resilience: For mission-critical jobs, prefer UTC schedules or orchestrators like Kubernetes CronJobs.
  3. POSIX vs Quartz: Quartz supports optional year and ? placeholders—ensure your platform matches.
  4. Observability: Export JSON to ticketing systems so reviewers know exactly what will run.

FAQ

Does this support Quartz?

Yes. Populate the optional year field or use ? in day-of-month/day-of-week to mimic Quartz triggers.

How are next runs calculated?

We iterate minute-by-minute from the current browser time and stop after five matches.

Can I share the configuration?

Use the Share button—your cron string is embedded in the query string so teammates open the same schedule.

References

  1. Vixie cron — crontab(5)
  2. Quartz Scheduler – Cron Trigger
  3. Kubernetes CronJob best practices
  4. AWS EventBridge cron reference

Author & Reviewer

Pawan has shipped scheduling systems for fintech workloads and brings that experience to CalcArena’s automation calculators.

Reviewed by Kushal Singh to ensure parity with current platform cron syntax.