Cron Expression Parser

How to Use the Cron Parser

1. Enter a cron expression in the input field, or click a preset chip for common schedules.
2. View the description — a human-readable explanation of when the job will run.
3. Check next run times — the tool calculates the next 5 execution times from the current moment.
4. Review the field breakdown — a table showing what each of the 5 fields means for your expression.

Understanding Cron Expressions

Cron is a time-based job scheduling system used in Unix-like operating systems. A cron expression uses five fields to define a schedule, and the cron daemon checks every minute whether the current time matches any scheduled expression. When a match occurs, the associated command is executed. Cron is the backbone of automated task scheduling across servers, CI/CD pipelines, cloud functions, and container orchestration systems.

The Five Cron Fields

A standard cron expression consists of five space-separated fields, each representing a time unit:

• Minute (0-59) — which minute of the hour the job runs
• Hour (0-23) — which hour of the day (in 24-hour format)
• Day of Month (1-31) — which day of the month
• Month (1-12) — which month of the year
• Day of Week (0-6) — which day of the week (0 = Sunday, 1 = Monday, ... 6 = Saturday)

Special Characters

• Asterisk (*) — matches every possible value for that field. * * * * * runs every minute.
• Comma (,) — specifies a list of values. 0 8,12,18 * * * runs at 8 AM, noon, and 6 PM.
• Hyphen (-) — defines a range. 0 9-17 * * * runs every hour from 9 AM to 5 PM.
• Slash (/) — defines a step. */15 * * * * runs every 15 minutes. 0 */2 * * * runs every 2 hours.

Common Cron Expressions

• * * * * * — every minute
• 0 * * * * — every hour at minute 0
• 0 0 * * * — daily at midnight
• 0 0 * * 0 — every Sunday at midnight
• 0 0 1 * * — first day of every month at midnight
• 0 9 * * 1-5 — every weekday at 9 AM
• */5 * * * * — every 5 minutes
• 0 0 1 1 * — every January 1st at midnight (yearly)

Cron in Modern Platforms

Beyond traditional Unix crontabs, cron expressions are used in GitHub Actions (schedule trigger), AWS CloudWatch Events, Azure Functions Timer Triggers, Google Cloud Scheduler, Kubernetes CronJobs, and nearly every CI/CD platform. The syntax is largely consistent, though some platforms add a sixth field for seconds and support additional features like L (last) and W (nearest weekday). Use our Timestamp Converter to verify execution times in different timezones, or format your cron job's JSON config output with the JSON Formatter.

Debugging Cron Schedules

Common mistakes with cron include confusing the order of fields, forgetting that hours use 24-hour format, and not accounting for timezone differences between the server and the expected execution time. Always verify your expression with a parser like this tool before deploying to production. The "next 5 run times" feature is particularly helpful for confirming the schedule matches your expectations.