Quick Presets
Fields
Next 5 Runs
Build Cron Expressions Visually
Pick values field-by-field (minute, hour, day-of-month, month, day-of-week) or type a cron expression directly and the tool parses it, validates it, describes it in plain English, and previews the next five times the expression will fire starting from now. Edits propagate in real time between the visual builder and the text field so you can switch between the two freely.
This is the tool for authoring a Unix crontab line, a Kubernetes CronJob schedule, a GitHub Actions schedule trigger, an AWS EventBridge or Azure Scheduler rule, or a Supabase/Vercel cron definition — all of which share the classic five-field cron syntax. It is also good for debugging a schedule that runs more or less often than expected by showing the actual next-fire timestamps.
The full range of cron operators is supported: star for every value, comma lists (1,15,30), ranges (1-5), step values (*/5 or 0-30/10), and named values for months (JAN-DEC) and days of week (SUN-SAT). Twelve quick presets cover the common schedules (every minute, every 5/10/15/30 minutes, hourly, every N hours, daily at midnight, weekly, monthly, yearly) so you rarely need to write an expression from scratch.
Parsing and next-run calculation happen in your browser — no backend, so your schedule is never logged anywhere.
About this tool
Cron expressions define recurring schedules using 5 fields: minute, hour, day of month, month, and day of week. They're used in Unix crontab, CI/CD pipelines, Kubernetes CronJobs, and cloud schedulers.
- Visual field-by-field editor
- 12 quick preset schedules
- Next 5 runs preview
- Human-readable description
100% client-side. Your inputs never leave your browser. Ads via AdSense (consent required).
Frequently asked questions
How do I read a cron expression?
Paste a 5-field cron expression (minute, hour, day-of-month, month, day-of-week) and the tool emits a human-readable description and the next 5 scheduled run times in your local timezone. It supports standard operators — *, */n, a-b, a,b,c — and the common aliases @hourly, @daily, @weekly, @monthly, @yearly. Syntax errors are flagged with the field and reason so you can fix them immediately.
Is the cron parser free?
Yes, fully free with no signup. Parse unlimited expressions — handy when migrating schedulers, reviewing infrastructure-as-code, or making sure a "0 2 * * *" really does mean 2 AM. JSONCraft is free across every tool; the cron parser matches the rest with no gated features.
Does the cron parser upload my expression?
No. Parsing runs entirely in your browser. Nothing is transmitted or logged. Cron expressions rarely contain secrets themselves but often appear next to job names that reveal internal architecture; keeping them local is always the safer default.
Does it support aliases and extended syntax?
Standard aliases (@hourly, @daily, @weekly, @monthly, @yearly, @annually, @reboot) are recognized. The parser covers classic Unix 5-field cron; 6-field (with seconds, used by Quartz and Kubernetes CronJob in some variants) and 7-field (with year) are not standard and are not parsed. Day-of-week uses 0-6 where 0 is Sunday, matching most Unix crontabs.
When are day-of-month and day-of-week both restricted?
A classic gotcha: when both day-of-month and day-of-week are restricted (not *), cron treats them with OR — the job runs if either condition matches, not both. So '0 0 1 * 1' runs every 1st of the month AND every Monday. The parser spells this out in the human-readable description so you don't get bitten by the OR versus AND confusion.