Cron Expression Builder & Explainer

Developer Tool

Cron Expression Builder & Explainer

Build cron schedules visually, get a plain-English explanation of any expression, and see the next 10 exact run times. Supports Linux cron, AWS EventBridge, Kubernetes CronJob, and GitHub Actions syntax.

Cron Builder
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Minute
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*
Hour
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*
Day
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*
Month
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*
Weekday
Plain English
Or paste an existing expression to explain it
Common Schedules
Build Visually
Next 10 Scheduled Runs (your local time)

Understanding Cron Syntax

A cron expression has 5 fields separated by spaces: minute hour day-of-month month day-of-week. Each field can be a number, a range (1-5), a list (1,3,5), a step (*/15), or a wildcard (*).

The fields run left to right, from most frequent (minute) to least frequent (day of week). When a field is *, it means “every possible value” for that field.

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Plain English

Every expression is translated into a human-readable sentence explaining exactly when it runs.

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Next 10 Runs

See the exact dates and times for the next 10 executions in your local timezone.

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Multi-platform

Linux cron, AWS EventBridge, Kubernetes CronJob, and GitHub Actions syntax variants.

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Visual Builder

Build expressions by selecting options from dropdowns — no cron syntax knowledge needed.

Frequently Asked Questions

Historical inconsistency. In the original Unix cron, Sunday was 0. Some systems also accept 7 for Sunday for convenience. Most modern implementations accept both. This tool treats 0 and 7 as Sunday for compatibility.
AWS EventBridge uses a 6-field cron with an additional year field: minute hour day month weekday year. It also uses ? instead of * when day-of-month or day-of-week is unused (you can’t specify both). All times are in UTC.
The slash / means “step”. */15 in the minute field means “every 15 minutes starting from 0” — so at 0, 15, 30, and 45 minutes of every hour. 10/15 would mean starting at minute 10, then every 15 minutes: 10, 25, 40, 55.
In standard Linux cron, if both are specified (not *), the job runs when either condition is met (OR logic, not AND). This is a common source of confusion. In AWS EventBridge, you must set one to ? to avoid ambiguity.

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