Cron Expression Parser
Explain a cron schedule and its next runs.
Field order: minute(0-59) hour(0-23) day(1-31) month(1-12) weekday(0-7, 0/7=Sun). Supports *, */n, a-b, a,b,c.
Schedule
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Next 5 run times
Your expression is processed entirely in your browser — never uploaded or stored.
What is a cron expression?
A cron expression is a 5-field string (minute hour day month weekday) used by Linux and server schedulers to specify when a job runs. Enter an expression to get a human-readable schedule description and the next 5 run times based on the current time.
Fields & symbols
- Field order: minute(0-59) hour(0-23) day(1-31) month(1-12) weekday(0-7, both 0 and 7 mean Sunday)
- *: every value
- */n: every n units (e.g. */15 = 0,15,30,45)
- a-b: range from a to b (e.g. 1-5 = Mon-Fri)
- a,b,c: a list of values (e.g. 1,15 = the 1st and 15th of the month)
Note: Next run times are calculated using your browser's local time and time zone.
Privacy & processing
All parsing and calculation happen in your browser. Your cron expression is never uploaded or stored.
The 5-field syntax table, and how day/weekday combine with AND
A cron expression has five space-separated fields, in order: minute, hour, day, month, weekday. Each field has the following range.
| Field | Range | Note |
|---|---|---|
| Minute | 0-59 | - |
| Hour | 0-23 | 24-hour clock |
| Day | 1-31 | Dates that don't exist in a given month (e.g. Feb 31) never match |
| Month | 1-12 | - |
| Weekday | 0-7 | Both 0 and 7 mean Sunday |
A quirk unique to this tool: Standard POSIX cron combines the day and weekday fields with OR when both are restricted (not
*) — acting like "the 1st of the month OR every Monday." This tool always combines them with AND instead. Registering 0 0 1 * 1 on a real server runs at midnight on the 1st AND at midnight every Monday, but this tool only matches days that are both the 1st and a Monday (e.g. Feb 1, 2027). Always check your target scheduler's documentation before deploying.
7 common expressions, and the time zone trap
Common real-world cron expressions and what they mean (all verified with this tool).
| Expression | Meaning |
|---|---|
0 0 * * * | Every day at midnight |
0 9 * * 1-5 | Weekdays (Mon-Fri) at 9 AM |
*/15 * * * * | Every 15 minutes (:00, :15, :30, :45) |
0 0 1 * * | 1st of the month at midnight |
0 * * * * | Every hour on the hour |
30 18 * * 5 | Every Friday at 6:30 PM |
0 0 1 1 * | January 1 at midnight (New Year's) |
Time zone trap: This tool calculates next run times using your browser's local time zone. Real server crontabs run on the server OS's configured time zone (often UTC). For example, registering
0 9 * * * on a UTC server while intending 9 AM Korea time (KST, UTC+9) will actually run at 6 PM KST. Always check the server's time zone before deploying.
FAQ
What is a cron expression?
A cron expression is a 5-field string (minute hour day month weekday) used by Linux and server schedulers to specify when a job runs. For example, '0 9 * * 1-5' means run at 9 AM every weekday.
What does each field mean?
From left to right: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 both mean Sunday). '*' means "every value", '*/n' means "every n units", 'a-b' means "a range", and 'a,b,c' means "a list".
What does '*/15 * * * *' mean?
The minute field is '*/15' and everything else is '*', so it runs at minute 0, 15, 30, and 45 of every hour — in other words, every 15 minutes.
Why do both 0 and 7 mean Sunday in the weekday field?
In standard (POSIX) cron, weekdays normally run 0-6, but for compatibility with some implementations, 7 is also treated as Sunday. This page interprets both 0 and 7 as Sunday.
Is my cron expression sent to a server?
No. All parsing and next-run-time calculation happen entirely in your browser; your expression is never uploaded or stored.
What happens if I set both day and weekday?
Standard POSIX cron combines the day-of-month and weekday fields with OR when both are restricted, but this tool always combines them with AND. For example, '0 0 1 * 1' runs on the 1st of the month OR every Monday on a real server, but in this tool it only matches days that are both the 1st and a Monday.
What are some common expressions, like daily at midnight or weekdays at 9?
Common real-world expressions include '0 0 * * *' (daily at midnight), '0 9 * * 1-5' (weekdays at 9 AM), '*/15 * * * *' (every 15 minutes), '0 0 1 * *' (1st of the month at midnight), and '0 0 1 1 *' (Jan 1 each year).
What time zone are the next run times based on?
This tool calculates next run times using your browser's local time zone. Real server crontabs run on the server OS's time zone (often UTC), so always check the server's time zone before deploying to avoid schedule mismatches.
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