Cron Expression Generator and Explainer
Type a 5-field cron expression, see a plain-language explanation of when it runs, and get the next 5 run times from now. Everything is computed in your browser.
What Is a Cron Expression and How Do You Read One?
Cron is a job scheduler used on Linux and Unix-based systems to run tasks automatically at fixed intervals. A cron expression is made of 5 fields, left to right: minute, hour, day-of-month, month and day-of-week. Each field accepts an asterisk (*, meaning "every"), a single number, a comma-separated list (1,15,30), a range (1-5), or a step expression (*/5).
The 5 Fields and Their Ranges
| Order | Field | Range | Meaning |
|---|---|---|---|
| 1 | Minute | 0-59 | Which minute of the hour it runs |
| 2 | Hour | 0-23 | Which hour of the day it runs (24-hour format) |
| 3 | Day-of-month | 1-31 | Which day of the month it runs |
| 4 | Month | 1-12 | Which month of the year it runs |
| 5 | Day-of-week | 0-6 | 0 = Sunday, 6 = Saturday |
Example Expressions
| Expression | Meaning |
|---|---|
| * * * * * | Every minute |
| */15 * * * * | Every 15 minutes |
| 0 * * * * | Every hour, on the hour |
| 0 9 * * * | Every day at 09:00 |
| 0 9 * * 1 | Every Monday at 09:00 |
| 0 0 1 * * | At midnight on the 1st of every month |
When both day-of-month and day-of-week are restricted (neither is an asterisk), standard cron treats the match as an OR: a date matches if it satisfies either the day-of-month condition or the day-of-week condition. This tool implements that behavior correctly.
Frequently Asked Questions
What are the 5 fields in a cron expression and what order are they in?
A standard cron expression has 5 fields, left to right: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12) and day-of-week (0-6). For example 0 9 * * 1 means every Monday at 09:00.
What does */5 mean?
*/n is a step expression that picks values across the field's range every n units. In the minute field, */5 means every 5 minutes starting from 0 (0, 5, 10, 15, ...).
How is day-of-week numbered?
The day-of-week field ranges from 0 to 6, and 0 represents Sunday: 0 Sunday, 1 Monday, 2 Tuesday, 3 Wednesday, 4 Thursday, 5 Friday, 6 Saturday.