Cron Schedule Studio
Build a cron expression, inspect its fields and preview actual occurrences in your chosen timezone. Compare two schedules and export the preview as CSV, JSON or calendar events.
Build from individual fields
Five-field format: minute, hour, day of month, month, day of week. Optional seconds come first.
Save or open a project
Schedule preview
Choose a preset and preview the schedule.
This previews cron-parser behavior and does not install or run any job. Scheduler dialects and DST behavior can differ. Calendar export contains the displayed occurrences as individual one-minute events; it is not a recurring cron job. Coincidences compare only the two displayed samples.
Supported expression syntax
Lists, ranges, steps, month/day aliases, L and # follow the bundled cron-parser. Five-field expressions use seconds=0. Quartz year fields, commands, @reboot and hashed H fields are unsupported. When strict day checking is off, verify the scheduler’s day-of-month/day-of-week behavior.
Using Cron Schedule Studio
Build five- or six-field cron expressions, preview next or previous runs across timezones, compare schedules and export CSV, JSON or calendar events.
- Choose a preset or enter a cron expression and IANA timezone.
- Set an ISO start instant, direction and count. Optionally compare another expression, then preview.
- Inspect field expansions and occurrences; export CSV, preview JSON, calendar events or a reusable project.
Example
Try the included demonstration. Set an ISO start instant, direction and count. Optionally compare another expression, then preview.
Questions & answers
Does this run my scheduled task?
No. This calculates occurrences using bundled cron-parser 5.10.1. It does not install jobs, run commands or contact your server. Confirm your actual scheduler dialect and DST behavior before deploying.
Which cron format is supported?
Five fields are minute, hour, day of month, month and day of week; seconds are optional as the first field. Lists, ranges, steps, aliases, L and # follow cron-parser. Quartz year fields, commands, @reboot and randomized H fields are unsupported.
How do timezones and DST work?
The expression is evaluated in the chosen IANA timezone while the start is an absolute ISO instant with Z or an offset. UTC and local times are shown. DST transitions follow cron-parser’s rules and may differ from another scheduler.
What does the comparison count mean?
It counts identical UTC instants within the two displayed occurrence lists. It does not prove that schedules never overlap outside these finite samples.
What does the calendar export do?
It exports the first schedule’s displayed occurrences as individual one-minute events, using UTC instants. It does not encode an infinite recurrence or execute a task. Preview JSON retains both sampled schedules.
What are the limits?
Preview 1–100 occurrences, with a 12-second local worker timeout. Expressions allow 200 characters each, projects 32 KiB, and no automatic storage. Strict day-field checking rejects two restricted day fields.
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