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Cron Expression Generator Build cron expressions visually with presets, field editors, and next-run previews.

Cron Expression Generator illustration
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Cron Expression Generator

Build cron expressions visually with presets, field editors, and next-run previews.

1

Choose a Preset

Select from common schedules like "every hour" or "weekdays at 9 AM".

2

Customize Fields

Edit individual fields (minute, hour, day, month, weekday) as needed.

3

Preview and Copy

See the plain English description, next 5 runs, and copy the expression.

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What Is Cron Expression Generator?

The Cron Expression Generator helps you build standard 5-field cron expressions visually, without memorizing the cryptic syntax. Start with one of 12 common presets (every minute, every hour, weekdays at 9 AM, etc.) and customize individual fields as needed. The tool shows a real-time plain English description of your expression, calculates the next 5 scheduled runs, and provides a one-click copy button. Each field accepts standard cron syntax including wildcards (*), ranges (1-5), lists (1,3,5), and steps (*/5). The interface labels each field with its valid range and name, making it beginner-friendly while still supporting advanced expressions.

Why Use Cron Expression Generator?

  • 12 common presets for instant scheduling
  • Visual field editor with range hints
  • Real-time plain English description
  • Next 5 run preview for verification
  • One-click copy to clipboard
  • Supports all standard cron syntax (*, ranges, lists, steps)

Common Use Cases

Server Administration

Create cron jobs for backups, log rotation, and maintenance tasks.

CI/CD Pipelines

Schedule automated builds, tests, and deployments.

Data Processing

Set up scheduled data imports, ETL jobs, and report generation.

Monitoring

Configure periodic health checks and alerting schedules.

Application Tasks

Schedule email sends, cache clearing, and cleanup routines.

Technical Guide

The generator constructs a 5-field cron expression by concatenating the minute, hour, day-of-month, month, and day-of-week fields. The plain English description is generated by parsing each field and translating it to natural language. The next-run calculator iterates forward from the current time, checking each minute against all five fields using a matchesField() function that handles wildcards, step values (*/n), ranges (a-b), and lists (a,b,c). A safety limit of 525,600 iterations (1 year of minutes) prevents infinite loops for impossible expressions. Presets populate all five fields at once using predefined values.

Tips & Best Practices

  • 1
    Start with a preset and modify from there — it's faster than building from scratch
  • 2
    Always verify your expression by checking the "Next 5 Runs" preview
  • 3
    Use */5 for "every 5 minutes" patterns instead of listing specific minutes
  • 4
    Day-of-week uses 0-6 where 0 = Sunday (Linux cron convention)
  • 5
    Test expressions in a staging environment before deploying to production

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Frequently Asked Questions

Q What is a cron expression?
A cron expression is a string of 5 fields (minute, hour, day-of-month, month, day-of-week) that defines a schedule. Cron jobs use these expressions to determine when to run.
Q What does * mean in cron?
An asterisk (*) means "every" — it matches all valid values for that field. For example, * in the hour field means "every hour".
Q What does */5 mean?
The step notation */5 means "every 5th value". In the minute field, */5 means every 5 minutes (0, 5, 10, 15, ...).
Q Is this a 5-field or 6-field cron?
This generator produces standard 5-field cron expressions (minute, hour, day, month, weekday). Some systems add a seconds field — this tool does not include it.
Q Can I use day names like MON, TUE?
This generator uses numeric values (0-6) for days. Some cron implementations accept names, but numbers are universally supported.
Q How do I verify my expression?
The "Next 5 Runs" section shows exactly when your expression will next trigger, letting you verify it matches your intended schedule.

About This Tool

Cron Expression Generator is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.