Time & Data
Cron Explainer
Explain simple cron expressions and preview upcoming runs.
Supports common five-field cron expressions: minute hour day month weekday.
About Cron Explainer
Cron Explainer translates five-field cron expressions into plain language and previews upcoming run times.
Common uses
- Explain a scheduled job before changing it.
- Check whether a weekday or day-of-month field is restrictive.
- Preview the next runs for a simple maintenance task.
Good to know
Cron dialects vary. This explainer focuses on common five-field cron expressions and may not cover provider-specific extensions.
How to read cron
Read the five fields from minute to weekday, then preview upcoming runs. A schedule can look simple but behave unexpectedly when both day-of-month and weekday fields are restricted.
Provider differences
This tool focuses on common five-field cron expressions. Hosting platforms, CI services, and cloud schedulers may add seconds, years, macros, or timezone settings.
Common mistakes
Cron expressions usually do not include a timezone in the expression itself. Check the scheduler's configured timezone before relying on a preview.
Worked example: Scheduling a weekday task
0 9 * * 1-5
At 09:00, Monday through Friday
This is a common five-field expression. The actual timezone and the interaction between day fields depend on the scheduler, so confirm both in the target platform.
Technical reference
The behavior described on this page was reviewed against crontab(5) manual. External standards remain authoritative when their requirements differ from a browser implementation.
Before you rely on the output
- Confirm timezone, unit, precision, and source-system expectations before using converted values for scheduling, billing, legal, or operational deadlines.
- Privacy mode: inputs are processed locally in your browser and are not intentionally sent to an application server.