What is a cron expression?
A cron expression is a compact schedule that tells a cron scheduler when to run a recurring task. In a standard Linux crontab, five fields define the minute, hour, day of month, month, and day of week. The command to execute comes after those fields.
This online cron expression generator helps you turn a schedule into those five fields without memorizing the syntax. Use it to plan database backups, log cleanup, data imports, or recurring maintenance on a Linux server. The visual builder, syntax validation, and upcoming execution times let you check your schedule before adding it to your crontab.
How to generate a cron expression
- Choose a common schedule or configure each field in the visual builder.
- Switch to Edit expression to paste an existing schedule or enter ranges and lists.
- Review the matching values and next five execution times in UTC.
- Copy the expression into your scheduler and add your command where required.
Cron syntax: the five fields explained
A standard cron schedule contains five space-separated fields, in this order:
┌ minute (0–59)
│ ┌ hour (0–23)
│ │ ┌ day of month (1–31)
│ │ │ ┌ month (1–12)
│ │ │ │ ┌ day of week (0–7; Sunday = 0 or 7)
* * * * *| Operator | Meaning | Example |
|---|---|---|
* | Every value in a field | * in hour matches every hour |
, | A list of values | 0,30 in minute matches twice an hour |
- | An inclusive range | 1-5 in weekday means Monday–Friday |
/ | A step within a wildcard or range | */10 in minute matches 0, 10, 20, 30, 40, 50 |
Common cron expression examples
These examples cover minute intervals, daily jobs, weekday schedules, monthly tasks, and leap-year dates. The times are interpreted in your scheduler’s timezone; this generator previews them in UTC.
| Expression | Schedule |
|---|---|
* * * * * | Every minute |
*/15 * * * * | Every 15 minutes, starting at minute 0 |
30 2 * * * | Every day at 02:30 |
0 9 * * 1-5 | Monday through Friday at 09:00 |
0 0 1 * * | On the first day of each month at midnight |
0 0 29 2 * | February 29 at midnight in leap years |
Use your cron expression on a Linux server
Open your user crontab with crontab -e. Add the generated schedule followed by the command, using absolute paths where possible. For example, this entry runs a backup script every day at 02:30 in the scheduler’s configured timezone:
30 2 * * * /usr/local/bin/backup.shThe five-field expression controls timing only. Your server still needs a running cron service, an executable script, and the appropriate permissions. Check your scheduler’s timezone before relying on the UTC preview.
Cron expression generator FAQ
Does this support Quartz or cron expressions with seconds?
This generator supports five-field Linux-style cron. Six- or seven-field expressions, Quartz operators such as ?, L, W, and #, and @reboot are not supported. Common aliases including @hourly, @daily, @weekly, @monthly, and @yearly expand to five fields.
What happens if I specify both a day of month and a weekday?
With both day fields restricted, Linux cron runs when either matches. For example, 0 9 1 * MON runs at 09:00 on the first of every month and on Mondays. A day field beginning with an asterisk, including a wildcard step, instead uses both day matches together.
Why are there no upcoming runs?
A schedule can be syntactically valid without matching a date, such as February 31. The preview searches up to eight years ahead and shows any matches within that window.
Which timezone does the preview use?
All preview dates use UTC. Cron expressions do not contain a timezone; the scheduler determines it. Daylight saving transitions can affect execution in other timezones. See the Cronie crontab documentation for matching rules and timezone behavior.
Does the tool save or run my job?
No. Schedule generation and preview calculations happen in your browser. Copy the expression into your own scheduler to use it.
Related developer tools
- Unix timestamp converter — inspect timestamps from scheduled tasks.
- Regex tester — test patterns for processing job output.
- YAML to JSON converter — work with scheduler configuration files.
- Learn more about cron — read our cron guide.