cronexpression.tools
Cron Tester

Cron Expression Tester

Paste any cron expression to instantly validate it, see the next 10 run times in your timezone, and get a plain-English description.

Cron Expression
Valid

Every 5 minutes

Field Breakdown
minute
*/5
every 5th minute
hour
*
every hour
day
*
every day of month
month
*
every month
weekday
*
every day of week
Next 10 Run Times
  1. 1Thu, Apr 16, 09:10:00
    in 4m
  2. 2Thu, Apr 16, 09:15:00
    in 9m
  3. 3Thu, Apr 16, 09:20:00
    in 14m
  4. 4Thu, Apr 16, 09:25:00
    in 19m
  5. 5Thu, Apr 16, 09:30:00
    in 24m
  6. 6Thu, Apr 16, 09:35:00
    in 29m
  7. 7Thu, Apr 16, 09:40:00
    in 34m
  8. 8Thu, Apr 16, 09:45:00
    in 39m
  9. 9Thu, Apr 16, 09:50:00
    in 44m
  10. 10Thu, Apr 16, 09:55:00
    in 49m

Platform Compatibility

Cron syntax varies slightly across platforms. Here's what each supports.

crontab / Linux

5 fields: min hour dom month dow

Standard 5-field format. Runs in server local timezone.

e.g. */15 9-17 * * 1-5

GitHub Actions

5 fields (same as crontab)

Always runs in UTC. Maximum resolution is 1 minute.

e.g. 0 6 * * 1

Kubernetes CronJob

5 fields (same as crontab)

Uses the cluster's timezone by default. Supports .spec.timeZone in k8s 1.27+.

e.g. 0 */6 * * *

AWS EventBridge

6 fields: min hour dom month dow year

Adds a 6th 'year' field. Use '?' for either dom or dow (not both). UTC only.

e.g. 0 12 * * ? *

Cron Expression Tester — FAQ

How do I test a cron expression?

Paste your cron expression into the input field above. The tester instantly validates the syntax, translates it to plain English, shows the next 10 run times, and breaks down each field. No login required.

Why are my cron run times off by an hour?

Most likely a timezone mismatch. crontab runs in the server's local timezone, but tools like GitHub Actions and AWS EventBridge always use UTC. Use the timezone selector above to match your target environment.

My cron runs less often than expected — why?

Check for accidental constraints in multiple fields. For example, `0 9 1 * 1` means 'the 1st of the month AND a Monday at 9am' — which rarely aligns. Most platforms treat day-of-month and day-of-week as an OR, but AWS EventBridge requires a `?` in one of them.

What does */5 mean in a cron expression?

`*/5` means 'every 5 units'. In the minute field: `*/5 * * * *` = every 5 minutes. In the hour field: `0 */5 * * *` = every 5 hours on the hour. The `*/<n>` syntax means 'every nth value starting from the minimum'.

Can I test a 6-field cron expression (AWS EventBridge)?

This tester validates standard 5-field cron expressions. For AWS EventBridge's 6-field format (which adds a year field), remove the year field before pasting, or use the AWS console's built-in preview feature.

How do I run a cron job at a specific timezone?

Standard crontab uses the server's local timezone. Kubernetes CronJob supports `.spec.timeZone` (k8s 1.27+). GitHub Actions always runs in UTC. For other platforms, convert your desired local time to UTC before writing the expression.

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