Cron Expression Parser

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.

Cron Expression Parser Features

• Plain-English translation

  Every cron expression is translated into a readable sentence describing exactly when it fires, so you don't have to mentally parse five asterisk-separated fields.

• Next run times

  See the next several times the schedule will actually fire, calculated from the current date, to sanity-check the expression before deploying it.

• Field-by-field breakdown

  Each field (minute, hour, day-of-month, month, day-of-week) is broken out individually, making it easy to spot which part of a complex expression is wrong.

How to Use Cron Expression Parser

1. 1

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

2. 2

   The human-readable explanation appears immediately.

3. 3

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

Examples

0 9 * * 1-5

At 09:00 AM, Monday through Friday

*/15 * * * *

Every 15 minutes

0 0 1 * *

At 12:00 AM, on day 1 of the month

*/15 8-17 * * 1-5

Every 15 minutes, between 08:00 AM and 05:59 PM, Monday through Friday

0 0 * * 0

At 12:00 AM, only on Sunday

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

Common Mistakes to Avoid

✕Mixing up day-of-month and day-of-week fields.

✓Cron has five fields in the order minute, hour, day-of-month, month, day-of-week. Double-check which position you're editing — the two day fields are easy to confuse.

✕Assuming cron times run in your local timezone.

✓Most cron implementations (including most CI/CD platforms) run on UTC or the server's system timezone, not your browser's timezone. Confirm which timezone the target system uses.

✕Using both day-of-month and day-of-week with AND logic in mind.

✓When both fields are restricted (not *), standard cron treats them as OR, not AND — the job runs if either condition matches, which often surprises people.

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

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.

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