Cron Expression Tester

Paste any cron expression to instantly validate it and preview the next 10 run dates.

Presets:
Check your expression syntax. Cron has 5 fields: minute hour day-of-month month day-of-week.
Enter a cron expression above to see a human-readable translation.

Next 10 Scheduled Runs

UTC

Quick Reference: Cron Syntax

Field Range Special Characters Example
Minute0-59* , - /30 = at :30
Hour0-23* , - /8 = 8 AM
Day of Month1-31* , - /1 = 1st of month
Month1-12* , - /6 = June
Day of Week0-6* , - /1 = Monday

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The Ultimate Guide to Cron Expressions

A cron expression is a string of five (or sometimes six) fields separated by spaces that represents a set of times. Originally created for the Unix cron daemon, it has become the universal standard for scheduling recurring tasks across software engineering. Whether you are automating a Python script, setting up AWS EventBridge, or configuring GitHub Actions, you will need to understand cron syntax.

How to Read a Cron Expression

Standard cron expressions consist of 5 fields in the following order:

  1. Minute: 0-59
  2. Hour: 0-23
  3. Day of the Month: 1-31
  4. Month: 1-12 (or JAN-DEC)
  5. Day of the Week: 0-6 (where 0 is Sunday, or SUN-SAT)

Common Cron Operators

  • * (Asterisk): Means "every". For example, * * * * * means every minute.
  • , (Comma): Used to specify multiple values. For example, 0 8,10,12 * * * runs at 8 AM, 10 AM, and 12 PM.
  • - (Hyphen): Specifies a range. For example, 0 9-17 * * 1-5 runs hourly from 9 AM to 5 PM, Monday through Friday.
  • / (Slash): Used to specify step values. The most common is */5 * * * * which means "every 5 minutes".

Top 5 Most Common Cron Expressions

0 0 * * * Runs daily at midnight. Commonly used for daily database backups and nightly reports.
*/15 * * * * Runs every 15 minutes. Perfect for polling APIs or checking system health.
0 9 * * 1-5 Runs at 9:00 AM, Monday through Friday. Great for sending daily team summaries on Slack.
0 * * * * Runs at the top of every hour (e.g. 1:00, 2:00, 3:00).
0 0 1 * * Runs at midnight on the first day of every month. Typically used for monthly billing cycles.

Where should I host my Cron Jobs?

Once you have generated your perfect cron expression using the tester above, you need a place to actually run your code. Instead of renting a VPS and manually configuring `crontab` via SSH, modern developers use Serverless Cron platforms.

LiteLambda allows you to paste your Python code directly into the browser, attach your cron expression, and the platform will automatically execute your script in an isolated, secure environment exactly on schedule. It includes built-in alerting so you never have to wonder if your cron job silently failed.