Cron Expression Builder

FREEDeveloper

TOOLCron Expression Builder

Presets:

* * * * *

every minute

Minute

Every minute

Hour

Every hour

Day of Month

Every day of month

Month

Every month

Day of Week

Every day of week

Next 10 Execution TimesUTC

1Thu, Jan 1, 2026, 12:01 AM

2Thu, Jan 1, 2026, 12:02 AM

3Thu, Jan 1, 2026, 12:03 AM

4Thu, Jan 1, 2026, 12:04 AM

5Thu, Jan 1, 2026, 12:05 AM

6Thu, Jan 1, 2026, 12:06 AM

7Thu, Jan 1, 2026, 12:07 AM

8Thu, Jan 1, 2026, 12:08 AM

9Thu, Jan 1, 2026, 12:09 AM

10Thu, Jan 1, 2026, 12:10 AM

100% freeNo signupRuns in your browser

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About Cron Expression Builder

Cron syntax, codified in the POSIX standard, drives scheduled jobs across Linux servers, GitHub Actions, cloud functions, and workflow automation platforms like n8n. The 5-field format — minute, hour, day-of-month, month, day-of-week — is deceptively simple but error-prone in edge cases: "every weekday at 9 AM in business months" requires combining a weekday field with a month range, and a single field error can shift a billing job by hours or days without any runtime warning.

How It Works

The visual builder maps each UI control (dropdowns, checkboxes, step inputs) to the corresponding cron field and assembles the expression string in real time. As you interact with the controls, the English translation is regenerated by a parser that handles all special characters: * (wildcard), / (step), , (list), and - (range).

The next-execution calculator uses your browser's Intl.DateTimeFormat API to resolve the local timezone, then walks forward minute by minute from "now" evaluating each cron field against the candidate timestamp. The first 10 matching timestamps are collected and displayed with full date, time, and timezone offset.

In reverse (Explain) mode, the pasted expression is tokenized into its five fields and each field is translated into a prose description. A field of "*/15" becomes "every 15 minutes"; "1-5" in the weekday field becomes "Monday through Friday".

Who Is This For

A backend engineer setting up a database backup job builds the expression visually and verifies the next 10 execution times before deploying to production.

A developer configuring a GitHub Actions schedule workflow pastes an existing cron string to confirm it fires at the intended UTC time, not a timezone-shifted time.

An n8n workflow builder uses the tool to generate the correct cron expression for a weekly newsletter send at 10 AM every Tuesday in their local timezone.

A DevOps engineer reviewing an inherited cron job pastes the expression to get an instant English explanation without consulting a man page.

How to Use

1

Use the visual dropdowns to select minute, hour, day, month, and weekday

2

See the generated cron expression and its English explanation in real-time

3

Check the next 10 execution times to verify the schedule

4

Or paste an existing cron expression to decode and visualize it

Frequently Asked Questions

Standard 5-field cron format: minute, hour, day of month, month, day of week. This works with crontab, GitHub Actions, and most schedulers.

Yes. Switch to Explain mode, paste any cron string, and get the visual breakdown, English explanation, and next 10 runs.

Your browser's local timezone. The timezone name is displayed alongside the results.

The builder uses the standard 5-field POSIX cron format (minute, hour, day of month, month, day of week). Some systems like Quartz and AWS EventBridge use a 6-field format with a leading seconds field. Check your scheduler documentation — if it needs seconds, prepend "0" to a 5-field expression for on-the-minute execution.

* means every value in the field. / specifies step values (*/5 in minutes means every 5 minutes). , is a list separator (MON,WED,FRI). - defines a range (9-17 in hours means 9 AM to 5 PM). The builder inserts these automatically when you use the visual controls.

Standard POSIX cron has no direct "last day of month" token. A common workaround is to schedule for day 28 and use a script that checks if tomorrow is a new month, or use a scheduler that supports the L modifier (Quartz, Spring, and some cloud schedulers). The builder highlights when a cron expression may not fire in shorter months.