Cron Expression Explainer — Free Online Tool Explain five-field cron expressions in plain English and preview the next 10 run times in a selected timezone.
Use this free online Cron Expression Explainer directly in your browser. No signup required, no data leaves your device. Part of Utilier — a collection of 133+ developer utilities.
What is Cron Expression Explainer? A five-field cron expression defines a minute, hour, day of month, month, and day of week for recurring jobs. This offline explainer translates common syntax into plain language and previews the next ten matching execution times in a selected IANA timezone.
Why use cron explainer? Cron notation is compact enough to hide costly scheduling mistakes. A readable explanation and concrete next-run list reveal whether a job will run on the intended days and hours before it reaches production.
When to use cron explainer Use it for crontab entries, CI schedules, Kubernetes CronJobs, maintenance tasks, and scheduled reports. Verify the target scheduler's exact dialect because some systems support names, seconds, L, ?, or other extensions that a standard five-field schedule does not.
How to use cron explainer Enter a five-field expression and select the timezone used for the preview.
Enter the schedule: Use minute hour day-of-month month day-of-week, such as 0 */6 * * 1-5.Read the explanation: Confirm that steps, lists, ranges, and aliases describe the expected cadence.Select timezone: Preview in the zone where the scheduler is intended to run.Review next executions: Inspect the next ten dates, especially around weekends and daylight-saving transitions.Key features Plain-language description: Explains common five-field expressions and shortcut aliases.Timezone preview: Calculates upcoming runs using a selected IANA timezone.Next ten runs: Makes the resulting schedule visible before deployment.Common use cases CI maintenance: Validate a weekday job before adding it to a pipeline workflow.Operations: Check backup and cleanup schedules in the timezone used by a server.Kubernetes: Review a CronJob schedule before applying a manifest.Examples Every six hours on weekdays 0 */6 * * 1-5At minute 0 every six hours, Monday through Friday.Daily midnight job 0 0 * * *At 00:00 every day in the selected timezone.Technical reference Standard five-field cron order used by this tool.
Minute 0 through 59. Hour 0 through 23. Day of month 1 through 31; dates missing from a month do not run. Month 1 through 12. Day of week 0 through 6, with 0 representing Sunday; 7 is accepted as Sunday. Operators Use * for all values, comma-separated lists, hyphen ranges, and slash steps. Common mistakes to avoid Assuming cron uses your laptop timezone Why it happens: A scheduler normally evaluates fields in the server or configured job timezone.
How to avoid it: Select the deployment timezone for the preview and verify the runtime configuration.
Expecting day-of-month and day-of-week to be AND Why it happens: Traditional cron implementations commonly treat restricted day fields with OR behavior.
How to avoid it: Check the target scheduler documentation and avoid combining both unless its behavior is known.
Scheduling the 31st as a monthly task Why it happens: Months without a 31st have no matching date.
How to avoid it: Use a guaranteed date, or implement an explicit month-end rule in the scheduler dialect that supports it.
Frequently asked questions What does 0 */6 * * 1-5 mean? It runs at minute zero every six hours on weekdays.
Does the preview support seconds? No. This tool intentionally explains standard five-field cron syntax.
Why can a next-run list differ from my scheduler? Cron dialects, job timezone configuration, and daylight-saving behavior differ by platform.
Is the expression sent to a server? No. Parsing and run preview calculations occur locally.
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