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Crontab Calculator

Calculate cron expression execution times and generate expressions.

Cron Expression

Cron Expression Generator

Format: sec min hour day month weekday (6 fields) or min hour day month weekday (5 fields)

Next Execution Time

Enter a Cron expression to see results

Common Expressions

Description

Crontab time calculation tool helps developers parse and generate Cron expressions, visually displaying scheduled task execution times. Supports common expression templates, making it an essential assistant for server scheduled task configuration.

Use Cases

1

Server operations: Configure and verify scheduled backups, log cleanup tasks

2

Scheduled tasks: Set up periodic data synchronization and report generation

3

Development debugging: Verify Cron expression execution times meet expectations

4

Operations monitoring: Configure health check and alert task frequencies

5

Learning: Understand Cron expression syntax and execution logic

Instructions

1

Enter a Cron expression in the input box and click "Parse" to see a natural language description

2

Use the Cron expression generator to visually build expressions

3

View "Next Execution Time" to see when tasks will run

4

Click common expressions to quickly fill in common configurations

Notes

  • Supports both 5-field (min hour day month weekday) and 6-field (sec min hour day month weekday) Cron formats
  • * means "every", / means interval, - means range in expressions
  • Next execution times are calculated based on current time, for reference only

FAQ

Q

What is the difference between 5-field and 6-field Cron expressions?

A

5-field format (min hour day month weekday) is standard Crontab format for Linux system task scheduling. 6-field format (sec min hour day month weekday) is common in Java Spring frameworks, supporting second-level precision.

Q

How to set up execution every 5 minutes?

A

Use expression */5 * * * *, where */5 means every 5 minutes. You can also use 0,5,10,15,20,25,30,35,40,45,50,55 * * * * for the same effect.

Q

How to represent weekdays in Cron expressions?

A

In the weekday field, 0 and 7 both represent Sunday, 1 represents Monday, and so on. You can use ranges like 1-5 for weekdays, or comma-separated like 1,3,5 for Monday, Wednesday, Friday.