General
Is this tool free?
Yes, completely free. No signup, no paid tier. The site is supported by display ads (Adsterra). If your ad blocker hides them, the tools still work normally — there are no anti-adblock popups.
Does my cron expression get sent to a server?
No. Everything happens in your browser via JavaScript. The cron parser, translator, and next-run calculator all run client-side. We have no server-side logging of expressions.
Which cron flavor does the homepage explainer use?
Standard 5-field Unix cron. For Quartz, AWS, GitHub Actions, Kubernetes, Spring, Azure, Jenkins, GCP, Laravel, or Airflow, use the platform-specific tools — each enforces the right field count and special characters for that platform.
Syntax
What do the five fields mean?
Minute, hour, day of month, month, day of week — in that order. See our complete syntax guide for details.
What's the difference between */5 and 0-59/5?
They're equivalent — both mean "every 5 minutes starting from 0." */5 is more idiomatic.
Why does my expression with both day-of-month and day-of-week behave weirdly?
Unix cron uses OR semantics when both day fields are restricted — it fires when EITHER matches. So 0 0 15 * 1 fires on the 15th of every month AND every Monday. To get AND semantics, use Quartz or gate inside your script. See our gotchas section.
Platform questions
Why does GitHub Actions reject my */3 expression?
GitHub Actions enforces a 5-minute minimum. */3 would fire every 3 minutes — too aggressive. Use */5 or higher.
Why does AWS require a ? in one of the day fields?
AWS EventBridge uses Quartz-style cron where you can't restrict both day-of-month AND day-of-week simultaneously. The ? means "no specific value, use the other day field." See the AWS tool page for details.
How do I handle timezones?
It depends on your platform. UTC always for GitHub Actions and classic AWS EventBridge; configurable for Kubernetes 1.27+, GCP Cloud Scheduler, Spring, and Quartz. See our timezone guide.
What happens during Daylight Saving Time transitions?
Jobs scheduled in DST-observing timezones can be skipped (spring forward) or duplicated (fall back) within the 1-3 AM window. See our DST guide for three robust strategies.
Features
Can I share a link to a specific cron expression?
Yes — both the homepage explainer and the builder support a ?cron= URL parameter. So crontabsheet.com/?cron=0+9+*+*+1-5 loads the explainer with that expression pre-filled.
How accurate are the "next run" times?
Computed in your browser's local timezone. They search up to one year ahead. For Spring/Quartz/Jenkins H syntax, next-runs aren't shown because they depend on values not computable client-side.
Why doesn't the natural-language parser handle "every other Tuesday"?
Standard cron has no way to express bi-weekly schedules — the parser refuses rather than approximating badly. For workarounds, see our From English page, which explains what cron can and can't express.
Still have questions?
Contact us via the contact page. Bug reports, feature requests, and corrections are all welcome.