Cron Expression Parser
Validate five-field cron expressions and calculate their next five scheduled execution times in UTC.
Run tool
Schedule automated tasks with confidence by verifying standard five-field cron strings online. This parser analyzes your schedule specification across five standard positions: minute, hour, day of the month, month, and day of the week. After processing your entry, the tool computes the next five upcoming execution timestamps starting from the current UTC time, outputting each occurrence as a clear ISO-formatted date and time string. When both day-of-month and day-of-week fields contain specific constraints, the engine applies standard matching logic so an execution occurs whenever either condition is met. The schedule search scans forward up to ten years to locate valid dates. If an expression contains syntax errors, invalid values, or requires an interval with no matches within the ten-year limit, the tool flags the issue immediately. Use this utility to inspect recurring jobs, confirm interval spacing, and prevent scheduling surprises across servers and cloud workflows.
Instructions
- Enter a standard five-field cron expression into the input field or keep the default schedule.
- Ensure the expression defines five whitespace-separated fields: minute, hour, day of month, month, and day of week.
- Run the parser to validate the syntax and calculate the schedule.
- Review the generated list of the next five execution times formatted in UTC.
Examples
- Evaluate 0 0 1 * * to calculate midnight runs on the first day of every month.
- Check */15 9-17 * * 1-5 to verify schedules running every 15 minutes during standard weekday business hours.
FAQ
Which cron expression format is supported?
The tool expects standard five-field UNIX-style expressions representing minute, hour, day of the month, month, and day of the week. Six-field or non-standard formats are not supported.
In which time zone are the calculated execution dates presented?
All future execution times are calculated relative to the current UTC time and displayed with UTC identification.
How does the tool handle simultaneous day-of-month and day-of-week settings?
When restrictions are specified in both day fields, matching uses standard OR logic, meaning the schedule triggers whenever either the day-of-month or the day-of-week condition matches.
What happens if a schedule does not occur within the next ten years?
The parser searches up to ten years into the future. If no matching date is found within that window, the calculation indicates failure.