Crontab Simulator

Calculate execution counts, first/last run dates, and natural language breakdowns for cron schedules.

Crontab Configuration

Presets:

Cron Syntax Reference & Day Semantics

Standard Expressions

  • * * * * * Every minute
  • */15 * * * * Every 15 minutes
  • 0 9 * * 1-5 9:00 AM on weekdays
  • 0 0 1 * * Midnight on 1st of month
  • 0 12 1,15 * * 12:00 PM on 1st & 15th

5-Field Structure

  • Field 1 Minute (0 - 59)
  • Field 2 Hour (0 - 23)
  • Field 3 Day of Month (1 - 31)
  • Field 4 Month (1 - 12)
  • Field 5 Day of Week (0 - 6, 0=Sun)

DOM / DOW Semantics

In standard Vixie Cron (and croniter), when both Day of Month (field 3) and Day of Week (field 5) are specified with non-wildcard values, cron treats them as an OR condition.

The job runs whenever either the day of month OR the day of week matches. If one of the fields is *, it matches on all days specified by the other field.