SCHEDULE FIELD NOTES · 01
Read the schedule.
Check the next run.
Five-field cron describes calendar matches, not an interval timer. Start with an example, then check upcoming times in the zone your scheduler actually uses.
Five expressions to start with
| Expression | Meaning in the selected time zone |
|---|---|
*/15 * * * * | At minute 00, 15, 30 and 45 of every hour |
0 9 * * 1-5 | At 09:00 Monday through Friday |
0 0 1 * * | At midnight on the first day of each month |
30 2 * * * | At 02:30 every day, subject to daylight saving transitions |
0 9 1 * MON | At 09:00 on the first day of the month OR on Monday |
Download the example cheat sheet (CSV)
Check an expression in the builder ↗
The field order is minute hour day-of-month month day-of-week. Lists use commas, ranges use a hyphen, and steps use a slash. Sunday can be 0 or 7.
The rule that often surprises people
In this Vixie-style preview, when both day of month and day of week are restricted, either can match. 0 9 1 * MON does not mean “only when the first is Monday”. It includes every Monday and every first day of the month.
When one day field is *, the other controls the day. In Vixie-style parsing, a field beginning with a star (such as */2) also carries the wildcard flag: both day fields must then match. For example, 0 9 */2 * MON selects Mondays whose day-of-month is in 1, 3, 5, and so on. All other fields still need to match. Check your scheduler’s own documentation: Quartz, AWS, and other dialects can use different field counts or rules.
Steps reset within a field
*/15 in the minute field means minutes 0, 15, 30, 45. It does not mean 15 minutes after the job finishes. A schedule for day 31 has no match in a month with only 30 days.
Time zones are part of the schedule
Choose an IANA zone such as America/New_York or Europe/London. UTC has no daylight saving shifts. Your server may use a different default zone from your browser, so confirm its configuration before installing an expression.
For 30 2 * * * in New York, the local 02:30 time does not exist on March 8, 2026. After March 7 at 12:00 UTC, this preview’s next two runs are March 9 and March 10 at 06:30 UTC. A repeated local time at the autumn transition can appear twice.
Preview limits
The tool searches the next 370 days and returns up to five matches. An annual expression may show only one run. Zero matches within that horizon does not prove a schedule will never run. The builder does not run, install, or monitor your jobs.
Seconds, @daily aliases, and Quartz characters ?, L, W, and # are not supported. Read the privacy notice for optional analytics.
Reference
Linux crontab(5) manual — field and calendar rules. The examples describe this tool’s behavior; verify the requirements of your own system before using an output.
Implementation detail: Cronie’s day-field wildcard flags.