Cron is compact but easy to misread because of field order, weekday numbering, and time zones. A sentence is good for orientation; the future execution list is the final check, and both should stay visible.
DEVELOP.02 CRON PARSER
Cron Expression Parser
Expression, plain-language meaning, field details, and future dates update together on one screen. Common scenarios live in the reference table and run when clicked.
CRON
Schedule expression
Waiting for an expression
Upcoming execution times
§ 01
Common Cron scenarios & quick insert
Click a row to select the matching field mode and fill the expression. The reference examples are executable presets.
Scenario
Expression
Mode
§ 02
Inspect future dates before trusting a description
§ 03
How to read a Cron expression
1
Confirm the field mode
Linux Crontab usually has 5 fields, some schedulers add seconds for 6, and Quartz often uses 7 with a year.
2
Enter the expression
Every edit validates numeric ranges and explains wildcards, steps, ranges, and lists field by field.
3
Inspect future dates
Switch between local and UTC and verify several upcoming runs instead of relying only on a sentence about weekdays or time zones.
§ 04
Frequently Asked Questions
Q1What is the difference between 5- and 6-field Cron?
A 5-field expression begins with minutes and is common in Linux Crontab. A 6-field expression adds seconds at the front and appears in some Java and Node schedulers. They are not directly interchangeable.
Q2What do *, /, -, and comma mean?
The wildcard means any value, slash means a step, hyphen means a range, and comma means several discrete values. A step in the minute field schedules a fixed minute interval.
Q3What happens when both day of month and weekday are restricted?
Standard Crontab commonly treats them as an OR when both are restricted. Quartz more often uses a question mark to leave one unspecified. This tool applies the basic semantics of the selected mode.
Q4Why are results several hours away from the server schedule?
The most common cause is a UTC server and a local browser. Switch the calculation zone and check the scheduler platform's own time-zone configuration.
Q5Are Quartz L, W, and # supported?
The current version supports seven fields, the question-mark wildcard, numbers, ranges, lists, and steps. It explicitly rejects L, W, and # instead of returning a misleading date.