Cron Expression Explainer
Build and explain common five-field cron schedules. Your work stays on this device whenever possible.
How to use Cron Expression Explainer
- On the "Schedule Builder" tab, pick "Frequency / Cadence": Every X Minutes, Hourly, Daily, Weekly (Specific Days) or Monthly.
- Set "Execution Time (HH:MM)", which defaults to 09:00, or for the minutes cadence choose "Run every N minutes" from 1 to 30.
- For Weekly, tick Mon to Sun under "Run on Days of Week"; for Monthly, enter a value in "Day of Month (1-31)".
- Open "Raw 5-Field Editor" to type Minute, Hour, Day, Month and Weekday fields directly, or "Popular Presets" for seven ready-made expressions.
- Read the dark expression banner, the "Plain-English Meaning" line and "Next 10 Scheduled Execution Times", then press "Copy Expression".
Worked example
Choose Weekly, set the time to 08:30, and untick Tue and Thu so Mon, Wed and Fri remain. The banner shows 30 8 * * 1,3,5 and the Plain-English Meaning line reads "At 08:30 on Monday, Wednesday, Friday". The list beneath shows the next ten matching mornings in your local zone. Copy Expression puts just the five fields on the clipboard.
When to use this tool
- Writing the crontab line for a nightly backup without memorising field order.
- Checking that an expression from a colleague really means weekdays only.
- Picking a safe every-15-minutes schedule for a polling script.
Important limitations
Generates standard 5-field UNIX crontab expressions (minute, hour, day of month, month, day of week). Quartz 6-field or 7-field formats containing seconds and years should be adapted to the hosting platform specifications.
Comparing alternatives
Other options for cron expression explainer include Crontab.guru, Cronmaker, FreeFormatter, CronTab.
ToolkitPoint is not affiliated with those services.
Frequently asked questions
Which cron dialect is produced?
Standard five-field Unix cron: minute, hour, day of month, month and day of week. There is no seconds field and no Quartz symbols such as ? or L, so expressions for Quartz-style or some cloud schedulers need adapting by hand.
In what time zone are the upcoming runs listed?
Your browser's local zone, worked out by stepping forward minute by minute. A server that runs in UTC will fire at a different hour, so check the scheduler's own zone setting before trusting a 09:00 preview.
Which syntax does the preview understand?
Asterisks, steps like */5, comma lists of single numbers and simple ranges such as 1-5. Mixed forms like 1-3,7 or 0-30/10, and names like MON, are not interpreted by the preview or the English text, so those lines can be wrong even when the cron itself is valid.
What if I fill in both day of month and weekday?
Real cron fires when either field matches, but this preview requires both, so it may list fewer runs than your scheduler will produce. Keep one of the two as an asterisk when in doubt.
How do Hourly and Monthly behave?
Hourly uses only the minutes from the time field, so 14:20 yields 20 * * * *. Monthly with day 31 skips months lacking one. Raw fields are not range-checked, so a minute of 61 is accepted without complaint.