UTILITIES WORKSPACE
Cron Explainer
Inspect a numeric five-field cron expression.
Input is processed on this site only when you run the tool. The application does not save inputs or results.
input.txt
Result result.json
A little clarity goes here.
Run the tool to see your result.
Result preview
UTF-8 text, at most 256 bytes per input. Tab leaves the editor. Plain text disables syntax colors. Browser textareas may normalize line endings to LF.
{"explain":{"inputMode":"text","options":[],"inputLabels":[],"inputLimits":[]}}{"explain":{"input":"*\/15 9-17 * * 1-5","options":[]}}A QUICK WALKTHROUGH
A familiar workflow,
with room to focus.
Enter five numeric fields: minute, hour, day, month and weekday.
Explain to expand the allowed values for each field.
Read the day matching rule; no job or schedule is created.
When to use Cron Explainer
Review the allowed values of a numeric five-field cron fixture before configuring a scheduler elsewhere.
Read the result
The result expands fields and states the day matching rule. It does not schedule a command, predict the next run, handle timezones or guarantee a possible calendar date.
SEE IT IN PRACTICE
Worked examples
Sample input. A result you can inspect.
Explain example
Input
*/15 9-17 * * 1-5
Expected result
{"minute":[0,15,30,45],"hour":[9,10,11,12,13,14,15,16,17],"dayOfMonth":[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"month":[1,2,3,4,5,6,7,8,9,10,11,12],"dayOfWeek":[1,2,3,4,5],"dayRule":"dayOfMonth AND dayOfWeek","explanation":"Calendar constraints: minute [0, 15, 30, 45], hour [9, 10, 11, 12, 13, 14, 15, 16, 17], month [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. Day-of-month [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31] AND weekday [1, 2, 3, 4, 5] must match. Weekday 0 means Sunday.","notice":"Numeric five-field Vixie-style subset. Sunday is 0. Values describe calendar constraints; no next-run, timezone or DST prediction."}{"kind":"properties","title":"At minutes 0, 15, 30, 45 during hours 9\u201317","fields":[{"label":"Minute","value":"0, 15, 30, 45"},{"label":"Hour","value":"9\u201317"},{"label":"Day of month","value":"Every day of month"},{"label":"Month","value":"Every month"},{"label":"Weekday","value":"Monday\u2013Friday"}],"note":"The day-of-month and weekday constraints must both match. Numeric five-field Vixie-style subset. Sunday is 0. Values describe calendar constraints; no next-run, timezone or DST prediction.","schema":1}Formats, limits and common errors
Check five fields, numeric ranges and positive supported steps.
- Defined Vixie-style numeric subset: *, lists, ascending ranges, */step and range/step. Sunday is 0, not 7. No names, aliases, wrapping ranges, seconds/year or L/W/#/?.
- Steps are anchored to the wildcard field minimum or range start. When neither day field starts with *, day-of-month OR weekday matches; otherwise both constraints apply. Impossible calendar combinations can still have valid fields.
- No next-run prediction, timezone/DST evaluation or operating-system scheduling. The explainer does not execute commands.
- Input: 256 UTF-8 bytes per text field. Output: at most 524,288 UTF-8 bytes; serialized responses have a separate 1 MiB ceiling. Size/work failures return no partial result.