ToolKitSphereCron Expression Parser & Next Run Preview
Parse 5-field cron expressions and calculate upcoming execution schedules.
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This cron expression tester parses standard 5-field cron syntax and calculates the upcoming execution times, so you can confirm a schedule is correct before deploying it to a real crontab or scheduled job. It's a must-have for developers and sysadmins who've ever second-guessed whether '0 */2 * * *' really means every two hours, or accidentally scheduled a job to run every minute instead of every day. Rather than waiting to see if a job fires at the wrong time in production, this cron parser shows you the next several run times immediately, based on the exact expression you type. It supports standard minute, hour, day-of-month, month, and day-of-week fields, along with common special characters like asterisks, ranges, steps, and lists. As with all tools here, parsing happens entirely client-side - your schedule expression is never sent anywhere. Type a cron expression below to see it validated and its next run times calculated instantly.
Features
- Parses standard 5-field cron expressions (minute hour day month weekday)
- Calculates and lists the next several scheduled run times
- Supports wildcards, ranges, steps, and comma-separated lists
- Validates syntax and flags invalid field values
- Shows results in your local time zone
- Instant recalculation as you edit the expression
- Recognizes common shorthand like */5 and 1-5
Why use this cron expression parser & next run times?
- Instant validation before deploying a real cron job
- Fully private - schedule expressions never leave your browser
- Accurate next-run calculation based on standard cron semantics
- Prevents costly scheduling mistakes in production systems
- Free with unlimited testing
Frequently asked questions
What do the five fields in a cron expression represent?
In order, they are minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6, where 0 is Sunday).
What does '0 */2 * * *' mean?
It means 'run at minute 0 of every 2nd hour', so the job fires at 00:00, 02:00, 04:00, and so on throughout the day.
Can I use both day-of-month and day-of-week in the same expression?
Yes, but most cron implementations treat these fields as OR'd together rather than AND'd when both are restricted from the wildcard.
What does an asterisk (*) mean in a cron field?
An asterisk means 'every value' for that field, e.g. an asterisk in the hour field means the job can run in any hour.
How do I schedule a job to run every weekday at 9am?
Use '0 9 * * 1-5', which runs at 9:00 AM on Monday through Friday.
What time zone are the calculated next-run times shown in?
Results are shown in your browser's local time zone by default, matching how most cron daemons interpret the system's local time unless configured otherwise.
Does this tool support 6-field cron expressions with seconds?
This tool focuses on the standard 5-field format used by Unix cron; some schedulers like Quartz add a seconds field, which isn't the default here.