Cron Expression Generator & Humanizer
Build a schedule, understand each field and preview upcoming runs in UTC.
Build your schedule
Your schedule
Next 5 runs · UTC
Calculated after the current minute. Preview searches up to 5 years ahead.
How to use it
- 1Start from a preset or type an expression
Pick a common schedule, then adjust the five fields.
- 2Read the plain-English summary
Each field is explained, so you can confirm the schedule says what you meant.
- 3Check the next runs
Upcoming run times are listed in UTC so you can sanity-check before saving the job.
Good to know
Standard five-field cron
Minute, hour, day of month, month and day of week, with *, lists, ranges, steps and JAN–DEC / SUN–SAT names.
Sunday is 0 or 7
Both spellings are accepted, matching common cron implementations.
Quartz extensions are not supported
Seconds fields, ?, L, W, # and @macros are outside this five-field syntax.
Either day field can match
When both day-of-month and day-of-week are restricted, cron runs on days matching either one, which surprises most people.
Common uses
- Scheduling a nightly database backup
- Setting up a weekday-only report
- Checking what an inherited crontab line actually does
- Planning a job that runs every 15 minutes
- Explaining a schedule in a pull request
Questions
How do I run a job every 15 minutes?
Use */15 in the minute field and * elsewhere. The preview lists the next run times so you can confirm.
What does * mean?
Every value for that field. A * in the hour field means every hour.
Why does my schedule run more often than expected?
If you restrict both day of month and day of week, standard cron runs when either matches, not only when both do.
Which timezone are the previews in?
UTC. Your server may use local time, so check its timezone before relying on the exact hour.
Standard five-field cron
Minute · Hour · Day of month · Month · Day of week. Supports *, lists, ascending ranges, steps and JAN–DEC / SUN–SAT names. Sunday can be 0 or 7. Seconds, Quartz ?, L, W, # and macros are not supported.
When both day fields are restricted, either matching day can run the job. Preview uses UTC; configure your scheduler accordingly. Local timezone and daylight-saving rules can change execution times. Cron syntax reference.