Tool Lockers guide
Cron Expression Cheat Sheet: Fields & Examples
Understand the five cron fields, common schedules, special characters, and time-zone details to check before deploying a job.
By Tool Lockers
The five cron fields
A common Unix-style cron expression has five fields, in this order:
minute hour day-of-month month day-of-week
For example, 30 9 * * 1-5 means minute 30 of hour 9 on weekdays, subject to the scheduler's time zone and dialect. The five-field form is common, but not universal: some schedulers add a seconds field or special syntax. Always check the target scheduler's documentation.
| Field | Typical range | Example |
|---|---|---|
| Minute | 0–59 | 15 means at minute 15 |
| Hour | 0–23 | 9 means during the 9 AM hour |
| Day of month | 1–31 | 1 means the first day of a month |
| Month | 1–12 | 1,7 means January and July |
| Day of week | 0–6 or 1–7 | Numbering varies by implementation |
Useful operators
*means every allowed value in that field.,lists alternatives, such as0,30for minutes 0 and 30.-specifies a range, such as1-5for a weekday-number range./specifies a step, such as*/15for every 15 values in the field.
Some schedulers support names such as MON or extensions such as L, W, and #; these are not portable across all cron implementations.
Common examples
| Expression | Common five-field interpretation |
|---|---|
0 * * * * | At the start of every hour |
*/10 * * * * | Every ten minutes |
0 8 * * 1-5 | At 8:00 on weekdays |
30 6 1 * * | At 6:30 on the first day of each month |
0 0 * * 0 | At midnight on Sunday where Sunday is 0 |
The meaning of day-of-month and day-of-week together varies between implementations. Do not assume that 1 means Monday everywhere, or that all schedulers interpret time in the same zone.
Check schedules before deployment
Cron expressions describe wall-clock schedules, not elapsed intervals. Daylight-saving changes can skip or repeat local times, and managed schedulers may evaluate schedules in UTC or a configured time zone. A job that runs hourly is usually better represented by a scheduler interval than by a local-time cron expression if elapsed time is the real requirement.
Enter an expression in the Cron Expression Parser to inspect upcoming run times. Confirm the expression's field count, time zone, day-of-week convention, and special syntax against the scheduler where the job will run. Test the production schedule in a safe environment before relying on it for billing, backups, or other important tasks.