What is a cron expression?

A cron expression is a string comprising five or six fields separated by white space that represents a set of times, normally as a schedule to execute some routine.

Why does 0 0 * * * mean every day at midnight?

The first zero represents the 0th minute, and the second zero represents the 0th hour (midnight). The asterisks mean every day of the month, every month, and every day of the week.

Does day of the week start on Sunday or Monday?

In standard cron syntax, 0 represents Sunday, 1 is Monday, and 6 is Saturday. Some implementations also allow 7 to represent Sunday.

What timezone does this tool use?

The "Next Scheduled Runs" section automatically calculates the dates and displays them using your local system timezone, making it easy to read without doing mental UTC conversions.

Cron Expression Builder & Parser – Free Dev Tool

Understand and Debug Cron Jobs Easily

Cron expressions are notoriously difficult to read, write, and debug. Even experienced Linux administrators and DevOps engineers frequently forget whether 1-5 means Monday-Friday or Sunday-Thursday. Our Cron Builder & Parser removes the guesswork by instantly translating the standard 5-part string into plain English.

How to Read a Cron Expression

A standard Linux or Kubernetes cron schedule consists of five space-separated fields:

Minute: 0 to 59
Hour: 0 to 23 (Military time)
Day of Month: 1 to 31
Month: 1 to 12 (or JAN-DEC)
Day of Week: 0 to 6 (Sunday to Saturday)

You can use special characters to modify these fields:

* (Asterisk) means "every" value (e.g., every minute).
, (Comma) separates multiple specific values (e.g., 1,15 means the 1st and 15th).
- (Hyphen) defines a continuous range (e.g., 1-5).
/ (Slash) specifies increments or steps (e.g., */5 in the minute field means every 5 minutes).

Key Benefits

Plain English Translation: Type 0 9 * * 1-5 and instantly see "At 09:00 AM, Monday through Friday".
Next Execution Dates: The tool automatically calculates the next 5 dates your job will run, displayed in your local computer's timezone so you don't have to manually convert UTC times.
100% Client-Side Privacy: Like all TechAlmirah tools, this is completely secure. It processes everything locally inside your browser memory. We never send your schedules to our servers.
Quick Templates: Don't want to write the expression from scratch? Click one of our quick templates for common schedules like "Every day at midnight".

Common Use Cases

Kubernetes CronJobs: Verifying the schedule string in a K8s manifest before applying it to production.
Linux Crontab: Debugging why a backup script on an Ubuntu server didn't run over the weekend.
GitHub Actions: Writing the `on.schedule.cron` syntax to trigger a workflow every Monday morning.

Related Engineering Tools

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Frequently Asked Questions

What is a cron expression?: A cron expression is a string comprising five or six fields separated by white space that represents a set of times, normally as a schedule to execute some routine.
Why does 0 0 * * * mean every day at midnight?: The first zero represents the 0th minute, and the second zero represents the 0th hour (midnight). The asterisks mean every day of the month, every month, and every day of the week.
Does day of the week start on Sunday or Monday?: In standard cron syntax, 0 represents Sunday, 1 is Monday, and 6 is Saturday. Some implementations also allow 7 to represent Sunday.
What timezone does this tool use?: The "Next Scheduled Runs" section automatically calculates the dates and displays them using your local system timezone, making it easy to read without doing mental UTC conversions.