Cron Expression Builder
Build cron expressions visually with an interactive editor. See human-readable descriptions and next 5 scheduled run times instantly.
Built by Michael Lip
Frequently Asked Questions
What is a cron expression?
A cron expression is a string of five fields (minute, hour, day of month, month, day of week) that defines a recurring schedule. It is used by cron daemons on Unix/Linux systems and by task schedulers in many frameworks.
What do the five cron fields mean?
Field 1: Minute (0-59). Field 2: Hour (0-23). Field 3: Day of month (1-31). Field 4: Month (1-12). Field 5: Day of week (0-6, where 0 is Sunday). An asterisk (*) means 'every' value in that field.
How do I schedule a cron job every 5 minutes?
Use the expression */5 * * * *. The */5 in the minute field means every 5th minute. Click the 'Every 5 min' preset button in this tool to set it automatically.
What does the slash (/) mean in cron?
The slash defines a step value. For example, */5 in the minute field means every 5 minutes (0, 5, 10, 15...). 1-30/2 means every 2nd value from 1 to 30 (1, 3, 5, 7...).
Can I use cron for seconds-level scheduling?
Standard cron uses 5 fields and its minimum granularity is one minute. Some systems (like Spring and Quartz) support a 6th field for seconds, but this tool focuses on the standard 5-field format.
How It Works
This tool runs entirely in your browser using vanilla JavaScript. No data is sent to any server. All conversions and calculations happen locally on your device, ensuring complete privacy.
EpochPilot uses the browser's built-in Intl.DateTimeFormat API and the IANA timezone database provided by your operating system. This means timezone conversions are always accurate, including Daylight Saving Time transitions.
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Privacy
Everything runs locally in your browser. No timestamps, dates, or personal data are transmitted to any server. The source code is open on GitHub.
Contact
EpochPilot is built and maintained by Michael Lip. For questions or feedback, email [email protected].