Cron is useful for scheduling backups, cleanup scripts and other recurring tasks. Its compact syntax can be difficult to read, especially when a schedule combines lists, ranges or several day restrictions. A valid expression can also run at the wrong time if the server uses a different time zone.
This cron builder and explainer helps you check a schedule before adding it to your system:
- Choose a schedule such as daily, weekdays or every few minutes. You can also paste an existing five-field cron expression.
- Read the explanation and check the individual fields. Under Advanced options, set the preview time zone and, optionally, the UTC reference date.
- Review the next five runs, then copy the expression into your scheduler.
The tool supports lists, ascending ranges, steps, month and weekday names, and common shortcuts such as @daily. It also explains a common surprise: restricting both day fields means that either one can match. Step values restart within their field, so */35 means minutes 0 and 35 of each hour. See the crontab manual for these matching rules.
Everything is calculated in your browser. It uses five-field cron matching, so check your scheduler's format, time zone and daylight-saving behaviour before using the result.
Build a schedule or paste a cron expression to understand it. Preview upcoming runs without installing anything.
Five fields: minute, hour, day of month, month, day of week. Paste the schedule only, without a command.
Advanced options
Choose your scheduler's IANA time zone. This changes the preview; the copied expression contains no time zone. The reference date above is always in UTC.
Supports *, lists, ascending ranges, range/wildcard steps, JAN–DEC, SUN–SAT and common @ aliases. Seconds, years, commands and Quartz syntax (?, L, W, #) are not supported.
Uses five-field cron matching: skipped local times do not run; repeated local times appear twice. Your scheduler may apply different daylight-saving rules. This tool previews schedules; it does not run or install jobs.
