Cron Parser

Read a Unix cron expression

A traditional Unix crontab expression has five fields in this order: minute, hour, day of month, month, and day of week. For example,0 9 * * 1-5 means at 09:00 on weekdays. An asterisk means all allowed values for that field. Lists such as 1,15, ranges such as 1-5, and steps such as */5 make a schedule more specific without writing every value.

This parser also accepts six fields with leading seconds. That format is useful for systems that support second-level schedules, but it is not the five-field format used by many Unix crontab files. Month names from JAN to DEC and day names from SUN to SAT are accepted. Both 0 and 7 mean Sunday for the day-of-week field.

Plain English and upcoming runs

After parsing, the tool shows a short explanation and the next ten run times. Upcoming values are generated from the current moment and displayed as ISO timestamps. The calculation is always in UTC, so the output does not change with the browser's local time zone or daylight saving rules. Use the displayed time zone explicitly when comparing a schedule with a server log.

When both day-of-month and day-of-week are restricted, Unix cron commonly treats a matching value in either field as a run. This detail can make an expression broader than it first appears. Check the next run list and the crontab documentation for the scheduler that will execute the expression. A parser can explain a schedule, but it cannot infer the business meaning of a job.

Supported scope and important limits

The supported nicknames are @yearly,@annually, @monthly, @weekly,@daily, @midnight, and @hourly.@reboot is intentionally rejected because it describes an event rather than a recurring UTC time. Quartz extensions such as a question mark, seven-field year expressions, L, W, and # are not Unix crontab syntax for this tool and are rejected.

Cron Parser is not a job runner, scheduler, alert system, or deployment service. It does not contact a server, save a crontab, trigger commands, inspect a machine, or tell you whether a process will finish on time. Treat the result as a review aid before placing an expression in the scheduler that owns the actual job.

Private schedule checks

The expression and calculated times stay in this browser. Nothing is uploaded while you paste, parse, copy, or inspect a sample. If a schedule is connected to an incident or deployment, remember that the expression itself may reveal operational details. For timestamp arithmetic and ISO values, compare the result with the Unix Timestamp tool.