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Cron Expression Tool

Explain cron expressions in plain English, preview upcoming runs, and generate Unix, seconds, or Quartz cron schedules.

Field builder

Updates the expression above

Next runs

    How to use this cron expression tool

    Use this tool when creating scheduled jobs for servers, background workers, CI tasks, reports, reminders, or maintenance scripts.

    1. Enter a cron expression or build one field by field.
    2. Choose the exact format when you know it, or leave detection on auto.
    3. Read the plain-English summary to catch obvious schedule mistakes.
    4. Check the next run times before pasting the expression into a job scheduler.

    Cron Expression Tool features

    • Paste a cron expression and read a plain-English schedule summary.
    • Auto-detect cron format or choose Unix, seconds, or Quartz formats.
    • Build cron expressions field by field.
    • Support optional seconds fields for six-field schedules.
    • Support Quartz-style year fields when needed.
    • Use examples and syntax help for minute, hour, day, month, weekday, and year fields.
    • Preview upcoming run times before using the expression.
    • Catch obvious schedule mistakes before pasting into a job scheduler.

    Cron formats supported

    This tool supports standard 5-field Unix cron, 6-field expressions with seconds, and Quartz-style 6-field expressions with ? for day-of-month or day-of-week. It handles common wildcards, ranges, lists, steps, month names, and weekday names in the browser.

    Cron syntax is compact, which makes it easy to paste into a scheduler and hard to read during review. The summary and next-run list are meant to catch mistakes such as running every minute instead of every hour, choosing the wrong weekday, or mixing Unix and Quartz field order.

    Use the format selector when your target scheduler is known. Linux crontab, GitHub Actions, cloud schedulers, Rails jobs, and Java Quartz schedulers do not all accept the same field count or special characters.

    How cron schedules are interpreted

    The tool normalizes the expression into seconds, minutes, hours, day-of-month, month, day-of-week, and optional year fields. It then turns the schedule into a plain-English explanation and calculates upcoming run times from the browser's current timezone.

    Next run previews are generated by checking the calendar fields against future times. They are a practical validation aid, but the scheduler that finally runs the job is still the source of truth for timezone, daylight saving behavior, and unsupported cron extensions.

    Cron expression FAQ

    Why does timezone matter for cron?
    Cron expressions describe calendar fields, not elapsed durations. The next run times shown here use your browser's timezone, while your server or scheduler may run in a different timezone.
    What is the difference between Unix and Quartz cron?
    Unix cron commonly uses five fields and starts with minutes. Quartz cron includes seconds and may include a year field, plus the ? placeholder for day fields.
    Should I trust the description or the next run list more?
    Use both. The description helps you understand the schedule, while the next run list is the practical check before using the expression.

    Built and maintained by utilkit. Found an issue? Send corrections to contact@utilkit.com

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