Free Cron Expression Parser Online
Free Cron Expression Parser Online is a free online tool by US AI. Paste any cron expression and instantly see what it means in plain English — with a field-by-field breakdown, validation, and the next 5 run times. It runs completely in your browser — no signup, no download, works on mobile and desktop.
📖 How to use
- Paste any 5-field cron expression, a 6-field (seconds) Quartz expression, or a special like
@daily, then press Parse. - Read the plain-English sentence, the per-field chips, and the next 5 run times in your browser's local timezone.
- Your work stays on your device; nothing is uploaded anywhere.
✨ Why use this tool?
US AI's free cron parser is fast, private and 100% free forever. It answers the question "what does this cron expression actually do?" in one second — perfect when you inherit someone else's crontab. Bookmark this page and share it with anyone who needs it.
❓ Frequently asked questions
What is a cron expression parser?
A cron parser does the reverse of a cron generator: you paste an existing cron expression and it explains what it means in plain English, shows a field-by-field breakdown, validates the syntax, and lists the next run times.
What does '*/5 * * * *' mean?
It runs every 5 minutes. The */N syntax means "every N units" — here, every 5th minute of every hour.
How many fields does a cron expression have?
Standard cron has 5 fields: minute, hour, day of month, month, and day of week. Some schedulers (like Quartz) add a 6th field for seconds at the start. Special strings like @hourly, @daily, @weekly, @monthly, @yearly and @reboot are shorthand for common schedules.
Why doesn't my cron job run at the expected time?
Two common causes: (1) when both day-of-month and day-of-week are restricted, cron uses OR logic, not AND — so "0 9 1 * 1" runs on the 1st of the month AND every Monday; (2) the job runs in the server's timezone, which may differ from your browser's local time. This parser shows times in your browser timezone, so compare them with your server's clock.
What do '* / - , @' mean in cron?
An asterisk (*) means any value, a slash (/) sets a step like */15, a dash (-) defines a range like 9-17, a comma (,) lists values like 1,15, and @ starts a special schedule string such as @daily or @reboot.
Is this cron parser free and private?
Yes — it is free forever, needs no signup, and everything runs in your browser. Nothing you paste is uploaded anywhere.