What do asterisks and slashes mean in cron syntax?

An asterisk (*) means 'every possible value' for that field; a slash (/n) defines a step interval, such as '*/5' meaning every 5 units.

Is this cron generator compatible with AWS EventBridge or Kubernetes?

Standard 5-field cron expressions are compatible with Linux crontab and Kubernetes CronJobs. AWS CloudWatch/EventBridge uses a 6-field variant including year.

Are my server schedule strings saved anywhere?

No. All crontab string parsing and execution time simulations run in browser memory.

Free & Private Online Browser Utility

Cron Expression Generator & Schedule Parser

Construct and explain standard 5-part cron schedule expressions directly in your browser. Configure minute, hour, day of month, month, and day of week schedules visually through intuitive controls, or paste existing cron strings to translate them into plain human-readable English. The tool computes upcoming scheduled execution timestamps without transmitting your backend job schedules over the network.

How to use

Step 1: Select Schedule Frequency

Choose a frequency preset (every 5 minutes, daily at midnight, weekly) or set custom fields.
Step 2: Customize Time Fields

Set minute, hour, and day constraints using visual selector pills or asterisks.
Step 3: Copy Crontab String

Copy the 5-field cron expression (e.g., */15 * * * *) or inspect the next 5 execution dates.

Options explained

Human-Readable Translation

Parses cron syntax into clear natural English sentences describing execution timing.

When to use: Use to verify complex crontab schedules before deploying to production servers.

Next 5 Execution Timestamps

Simulates the schedule forward to display the next 5 upcoming calendar trigger times.

When to use: Use to verify timezone offsets, daylight savings considerations, and month-end behavior.

Common Quick Presets

One-click templates for hourly, daily, midnight, weekly, and monthly maintenance scripts.

When to use: Use to quickly generate standard cron expressions for backup and cleanup tasks.

Worked example

Input: Schedule: Every 15 minutes between 9:00 AM and 5:00 PM on weekdays

Output: Cron expression: '*/15 9-17 * * 1-5' | English: 'At every 15th minute from 9 through 17 on every day-of-week from Monday through Friday'

Standard 5-part POSIX crontab format with minute, hour, day-of-month, month, day-of-week.

Tips & limits

Cron syntax uses 5 standard fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-6).
Day of week 0 represents Sunday in standard Linux crontabs, though some systems also accept 7 as Sunday.
Step values (*/10) specify intervals, such as running a script every 10 minutes.

Common problems

Cron job does not fire at the expected time on the server: Server clocks often run on UTC; verify whether your server timezone matches your local geographic timezone.
Both day of month and day of week specified: In standard crontab implementations, specifying both fields behaves as an OR condition, firing on either matching condition.

Frequently Asked Questions (FAQ)

What do asterisks and slashes mean in cron syntax?: An asterisk (*) means 'every possible value' for that field; a slash (/n) defines a step interval, such as '*/5' meaning every 5 units.
Is this cron generator compatible with AWS EventBridge or Kubernetes?: Standard 5-field cron expressions are compatible with Linux crontab and Kubernetes CronJobs. AWS CloudWatch/EventBridge uses a 6-field variant including year.
Are my server schedule strings saved anywhere?: No. All crontab string parsing and execution time simulations run in browser memory.

How to use

Step 1: Select Schedule Frequency

Step 2: Customize Time Fields

Step 3: Copy Crontab String