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Cron Expression Parser

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About Cron Expression Parser

The Cron Expression Parser translates cron schedule expressions into plain English and shows the next 5 scheduled run times. Paste any cron expression and instantly understand what it means, when it will next fire, and whether it contains a syntax error — all without memorizing the cron field order.

Cron expressions are used to schedule recurring tasks across virtually every backend platform: Linux crontab jobs, AWS Lambda EventBridge schedules, GitHub Actions workflow schedules, Kubernetes CronJobs, Heroku Scheduler, Jenkins pipeline triggers, Apache Airflow DAG schedules, and many application-level job queues.

The parser supports standard 5-field Unix cron syntax (minute hour day-of-month month day-of-week) and 6-field expressions with a leading seconds field (used by Spring Framework, Quartz, and AWS). Special shorthand strings @daily, @weekly, @monthly, @hourly, and @reboot are also recognized.

The 'Next run times' panel shows the upcoming 5 schedule dates and times in your local browser timezone, making it easy to verify that your expression fires at the exact intervals you intended — particularly useful for complex expressions like '0 9 * * 1-5' (weekdays) or '*/15 8-17 * * 1-5' (every 15 minutes during business hours on weekdays).

All parsing and scheduling runs locally in your browser. Nothing is sent to a server and no sign-up is required.

Practical Uses for Cron Expression Parser

  • Understand a cron schedule copied from a colleague's script
  • Verify a GitHub Actions workflow's schedule trigger fires when expected
  • Debug why a Kubernetes CronJob isn't running at the expected time
  • Check an AWS EventBridge schedule expression before deploying
  • Convert a plain-English schedule request into a valid cron expression
  • Verify a Jenkins pipeline's cron trigger syntax before saving

How to Use Cron Expression Parser

  1. Enter a cron expression like '0 9 * * 1-5'.

  2. The human-readable explanation appears immediately.

  3. The next 5 scheduled run times are shown with dates and times.

Examples

Example — Every weekday at 9am
Input
0 9 * * 1-5
Output
At 09:00 AM, Monday through Friday
Example — Every 15 minutes
Input
*/15 * * * *
Output
Every 15 minutes
Example — First of each month
Input
0 0 1 * *
Output
At 12:00 AM, on day 1 of the month
Example — Business hours every 15 min on weekdays
Input
*/15 8-17 * * 1-5
Output
Every 15 minutes, between 08:00 AM and 05:59 PM, Monday through Friday
Example — Midnight every Sunday
Input
0 0 * * 0
Output
At 12:00 AM, only on Sunday

Who Uses the Cron Expression Parser Tool

  • DevOps engineers verify Kubernetes CronJob and CI/CD pipeline schedule expressions before deployment.
  • Backend developers understand and debug cron expressions found in scheduled job configurations.
  • Site reliability engineers double-check AWS EventBridge or Cloud Scheduler cron syntax before a change goes live.
  • Data engineers verify ETL pipeline schedules run at the intended frequency and time.
  • Students learn cron syntax for a systems administration or DevOps course.

Comparisons

5-Field vs 6-Field Cron Syntax

Standard Unix cron uses 5 fields — minute, hour, day-of-month, month, day-of-week — which is what you'll find in a typical Linux crontab. This is the format most widely recognized and supported across platforms.

6-field cron adds a leading seconds field, used by frameworks like Spring Scheduler, Quartz, and some AWS services. When copying a cron expression between systems, check which format the target platform expects — a 6-field expression pasted into a 5-field-only system will be misinterpreted.

Frequently Asked Questions

What cron format is supported?

Standard 5-field Unix cron (minute hour day month weekday) and 6-field with seconds. Special strings @daily, @weekly, @monthly, @hourly, and @reboot are also supported.

What does '*/5' mean in a cron expression?

*/5 means 'every 5 units'. In the minute field, */5 means every 5 minutes (0, 5, 10, 15, ...).

What does 0 9 * * 1-5 mean?

It means 'at 9:00 AM every weekday (Monday through Friday)'.

What does 0 0 1 * * mean?

It means 'at midnight (00:00) on the 1st day of every month'.

What is the difference between 0 and *?

0 means 'at exactly minute/hour 0'. * means 'every minute/hour'. So '0 * * * *' runs at minute 0 of every hour, while '* * * * *' runs every single minute.

Does cron support timezones?

Standard cron runs in the system timezone. AWS EventBridge and some other platforms support timezone specification. The tool shows run times in your local browser timezone.

Why isn't my Kubernetes CronJob running when expected?

Paste your CronJob's schedule expression here to verify it means what you think — a common issue is confusing the day-of-month and day-of-week fields, or misunderstanding how */N step values work.

What does '0 0 * * 0' mean?

It means 'at midnight every Sunday' — the day-of-week field uses 0 for Sunday, 1 for Monday, through 6 for Saturday.

Can I convert a plain-English schedule into a cron expression?

This tool explains an existing cron expression in plain English rather than generating one from a description, but working backward from a similar example expression is often the fastest way to build your own.