Free Cron Expression Builder
Build and validate cron expressions visually — supports standard Unix cron and AWS EventBridge cron syntax. See a human-readable description and the next run times instantly. No sign-up, 100% in-browser.
Presets
Human-readable
Every minute
Next 5 run times (local time)
- 1 5/22/2026, 6:21:00 PM
- 2 5/22/2026, 6:22:00 PM
- 3 5/22/2026, 6:23:00 PM
- 4 5/22/2026, 6:24:00 PM
- 5 5/22/2026, 6:25:00 PM
Related Developer Tools
Last updated: May 21 2026
Reviewed by the QuickTooly Team
Cron Expression Builder Guide
Why Use QuickTooly's Cron Expression Builder?
- Visual field builder: Set each cron field with a dropdown — no need to memorise syntax.
- Human-readable output: See exactly when your cron will fire in plain English before deploying.
- AWS EventBridge support: Switch to 6-field AWS syntax with
?andyearsupport — a gap no other free tool fills. - Next run times: Preview the next 5 scheduled executions so you can verify your schedule is correct.
- Presets: One-click common patterns to get started instantly.
- 100% private: Everything runs in your browser — no data leaves your device.
Cron Expression Field Reference
A standard Unix cron expression has five fields separated by spaces:
| Field | Allowed values | Special chars |
|---|---|---|
| Minute | 0–59 | * , - / |
| Hour | 0–23 | * , - / |
| Day of month | 1–31 | * , - / ? L W |
| Month | 1–12 or JAN–DEC | * , - / |
| Day of week | 0–6 or SUN–SAT | * , - / ? L # |
AWS EventBridge Cron Differences
AWS EventBridge (formerly CloudWatch Events) uses a 6-field cron format wrapped in cron(…) and has several differences from standard Unix cron:
- Year field: An additional 6th field for the year (1970–2199 or
*). - ? required: You cannot specify both day-of-month and day-of-week; one must be
?. - No @reboot: AWS does not support special strings like
@hourly. - Weekday numbering: AWS uses 1=SUN … 7=SAT (not 0–6).
- Minimum resolution: The finest granularity is 1 minute.
Common Cron Patterns
| Expression | Meaning |
|---|---|
| * * * * * | Every minute |
| 0 * * * * | Every hour, on the hour |
| 0 0 * * * | Daily at midnight |
| 0 9 * * 1-5 | Weekdays at 9:00 AM |
| 0 0 * * 0 | Every Sunday at midnight |
| 0 0 1 * * | 1st of every month at midnight |
| 0 0 1 1 * | Every January 1st at midnight |
| */5 * * * * | Every 5 minutes |
| 0 */6 * * * | Every 6 hours |
| 30 8 * * 1 | Every Monday at 8:30 AM |
Frequently Asked Questions
What is a cron expression?
A cron expression is a string of 5 (or 6) fields that defines a recurring schedule for a task. It is used by Unix cron, AWS EventBridge, GitHub Actions, Kubernetes CronJobs, and many CI/CD systems to trigger jobs at specified intervals.
What does */5 mean in a cron field?
The / character denotes a step value. */5 in the minute field means "every 5 minutes" (0, 5, 10, …, 55). 0/15 means "starting at 0, then every 15 minutes."
How do I run a job every weekday?
Use 0 9 * * 1-5 to run at 9 AM Monday through Friday. The 1-5 in the day-of-week field represents Monday (1) to Friday (5).
Why does AWS EventBridge cron use ??
AWS requires that exactly one of day-of-month or day-of-week be set to ? (no specific value). This avoids ambiguity — for example, "the 15th of every month that is also a Wednesday" is tricky logic. Use ? for the field you don't care about.
What is the minimum cron interval on AWS EventBridge?
AWS EventBridge supports a minimum interval of 1 minute. For sub-minute scheduling you would need a different mechanism, such as Step Functions with a wait state.
Is my cron expression validated server-side?
No — validation and parsing run entirely in your browser using the open-source cronstrue and cron-parser libraries. No data is ever sent to a server.