How to Parse a Cron Expression
Enter the expression
Type or paste a standard 5-field cron string into the input box, for example 0 9 * * 1 for 9 AM every Monday. A 6-field string is also accepted; the leading seconds field is dropped and the remaining five are read as minute, hour, day of month, month, and day of week.
Parse it
Press Parse Expression or hit Enter. The tool validates every field against its allowed range and shows a clear error if a value is out of bounds or uses an unsupported form, so you can fix the syntax before relying on it.
Read the results
You get a plain English summary, a field-by-field breakdown of each value, and the next 10 run times computed from the current moment. All of this runs in your browser, so the expression stays on your device.
Cron Fields and Supported Syntax
A standard cron line has five space-separated fields, each with its own valid range. This parser understands the asterisk, step, range, and list operators in every field. The table below shows what each position controls and an example of accepted input.
| Field | Position | Range | Example | Meaning |
|---|---|---|---|---|
| Minute | 1 | 0 to 59 | */15 | Every 15 minutes |
| Hour | 2 | 0 to 23 | 9-17 | Each hour from 9 to 17 |
| Day of Month | 3 | 1 to 31 | 1,15 | On the 1st and 15th |
| Month | 4 | 1 to 12 | 6 | In June only |
| Day of Week | 5 | 0 to 6 (0 is Sunday) | 1-5 | Monday through Friday |
Which Operator Do You Need
Every value: *
Use the asterisk when a field should match all of its values. In the minute field it means every minute; in the month field it means every month. It is the most common building block of a schedule.
Steps: */n
Use a step to repeat at a fixed interval, such as */5 in the minute field for every five minutes. This parser reads the step form starting from the field minimum, so */2 in the hour field runs at 0, 2, 4 and onward.
Ranges: a-b
Use a hyphen for a continuous span, like 9-17 in the hour field for daytime hours. Both ends are inclusive and must stay within the field range, or the parser flags it as invalid.
Lists: a,b,c
Use commas to pick specific, non-adjacent values, such as 1,15 in the day-of-month field. In the month and day-of-week fields the breakdown also shows friendly names like Jan or Mon.
Common Problems and Fixes
Invalid cron expression error
The parser expects exactly 5 fields, or 6 when a leading seconds field is included. Make sure values are separated by single spaces and that you have not pasted extra columns such as a command or a user name from a crontab line.
A field is marked out of range
Each field has fixed limits: minute 0 to 59, hour 0 to 23, day of month 1 to 31, month 1 to 12, and day of week 0 to 6. A value like hour 24 or month 13 will be rejected. Adjust it to fall inside the allowed range.
Month or day names are not recognized
This parser works with numeric values, so use 1 for January and 1 for Monday rather than JAN or MON. The breakdown then displays the matching name back to you for confirmation.
Day-of-month and day-of-week both set
When both day fields use real values instead of an asterisk, standard cron treats them as OR, so the job runs on either matching day. If you expected an AND, leave one of the two fields as * and constrain only the other.