# Cron expression explainer

Explain a 5-field cron expression and show upcoming UTC run times. No commands are executed.

Privacy: The expression stays in your browser. No server request. Analytics never receive the expression text.
Methodology: Parses classic 5-field cron (minute hour day-of-month month day-of-week) with lists, ranges, and steps. Next runs are projected minute-by-minute in UTC. Day-of-month and day-of-week restrictions follow common OR semantics and are called out in warnings.
Network access: no
Stores input: no
Client-side only: yes
Canonical: https://fajita.io/tools/cron-expression-explainer

A cron expression describes when a job should run. Pair it with a heartbeat monitor to learn whether it actually ran.

Limitations:
- Not every platform uses identical cron syntax
- Seconds fields and some extensions are unsupported
- Timezone conversions around DST need human care