Cron Expression Parser — Decode & Explain Cron Schedules

This free cron expression parser translates cron schedules into plain English and shows when a job will next run. A standard cron expression has five fields — minute, hour, day-of-month, month, and day-of-week — each accepting numbers, lists, ranges, or steps like */5. It also explains the classic day-of-month / day-of-week OR-trap that surprises most people. Paste any expression to decode it instantly. Everything runs in your browser, and the tool assumes the server timezone your scheduler uses.

Description
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How cron expressions work

A cron expression is a string of 5 space-separated fields that define a recurring schedule: minute hour day-of-month month day-of-week. Each field accepts a specific value, a wildcard (* = every), a range (1-5), a list (1,3,5), or a step value (*/15 = every 15 units).

Examples: 0 9 * * 1-5 = 9:00 AM on weekdays. */15 * * * * = every 15 minutes. 0 0 1 * * = midnight on the 1st of every month. 0 */2 * * * = every 2 hours. Day-of-week: 0 or 7 = Sunday, 1 = Monday, …, 6 = Saturday. Cron runs in the server's local timezone unless configured otherwise — always set timezone explicitly in production systems using CRON_TZ or system-level settings. Some platforms use 6-field cron (adding seconds as the first field) or 7-field (adding year at the end).

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Reading the five fields

A standard cron expression has five space-separated fields: minute hour day-of-month month day-of-week. Each accepts a number, a list (1,15), a range (9-17), a step (*/5 = every five units) or * for "any". So 30 9 * * 1-5 means 09:30 on every weekday, and */15 * * * * means every fifteen minutes.

The day-of-month / day-of-week trap

When both day fields are restricted, cron treats them as OR, not AND — 0 0 13 * 5 fires on the 13th and every Friday, not only on Friday the 13th. This surprises almost everyone. Leave one of the two day fields as * unless you genuinely want the OR behaviour.

Handy shorthands

Many schedulers accept macros: @hourly, @daily, @weekly, @monthly and @reboot. Also remember cron runs in the server's timezone (often UTC) and silently skips or repeats jobs across daylight-saving shifts — schedule critical tasks away from the 1–3 a.m. window to avoid both.

⚠️ Common Mistakes to Avoid

Frequently asked questions

What is a Cron expression?

A string representing a schedule for running a command or script at specific intervals.

What does '0 0 * * *' mean?

This cron expression means the task will run every day at midnight (00:00).

Reviewed by the ToolsmithPro editorial team · Last updated June 2026. Every calculation and conversion runs entirely in your browser — your inputs are never uploaded, stored or shared. Formulas and methodology are documented on our about page; spot an error? tell us and we'll fix it.