Cron Expression Generator
Cron schedules are powerful but easy to get wrong. This free cron expression generator turns simple schedule fields — minute, hour, day of month, month and weekday — into a valid five-field expression, validates it, and shows you the next run time ahead of time. Build it, verify it, copy it — privately in your browser.
What is a cron expression?
A cron expression is a short string that tells a scheduler when to run a job. The classic form has five fields separated by spaces, each controlling one part of the schedule: minute (0–59), hour (0–23), day of month (1–31), month (1–12) and day of week (0–7, where both 0 and 7 mean Sunday). An asterisk in any field means "every value" for that unit, so 0 0 * * * runs at midnight every day, and */10 * * * * runs every ten minutes.
Because each field can also be a comma-separated list, a range, or a step expression, cron can express anything from a once-a-year job to a job that runs several times an hour on selected weekdays. That flexibility is why cron powers Linux, Docker, Kubernetes, GitHub Actions, and countless task schedulers.
This generator composes the five fields for you, validates every value against its allowed range, and then simulates the schedule to tell you the next time the job will actually fire. Everything runs in your browser.
How to use the cron expression generator
- Pick a quick preset, or enter your own values in the five fields.
- Watch the generated expression update as you type.
- Check the status — it tells you if any field is out of range.
- Read the plain-English description and the next run time.
- Click Copy expression to use it in your scheduler.
Example
Set the preset to Weekdays (Mon–Fri) at 09:00 and the tool builds 0 9 * * 1-5.
The description reads Runs at 09:00, on Monday through Friday, and Next run shows the next weekday at 09:00. Switch to Every 5 minutes and you get */5 * * * * with the next run about five minutes away.
Common use cases
- Setting up an automated backup, report or cleanup script in a server cron tab.
- Configuring scheduled jobs in GitHub Actions or a Kubernetes CronJob.
- Scheduling data pipelines, database dumps and nightly batch jobs.
- Automating recurring maintenance tasks so they run without manual effort.
Pro tips
- When both day-of-month and day-of-week are restricted, cron runs on a day matching either, not both.
- In cron, minute and hour are the two fields you adjust most; day fields default to
*. - Use step values such as
*/15for the minute field to run every quarter of an hour. - Always preview the next run before deploying a schedule — a valid expression can still fire at the wrong time.
FAQ
What is a cron expression?
A cron expression is a five-field string (minute, hour, day of month, month, day of week) that tells a scheduler exactly when to run a scheduled job.
What do the five fields mean?
Minute 0-59, hour 0-23, day of month 1-31, month 1-12, and day of week 0-7 where 0 and 7 are Sunday. An asterisk means every value.
How does the generator work?
You fill in the minute, hour, day, month and weekday fields, and it combines them into a valid 5-field cron expression and computes the next run time.
Is the cron expression validated?
Yes. Each field is checked against its allowed range and syntax, and the tool shows whether the expression is valid before you use it.
How is the next run time calculated?
The tool steps through time from the current minute and finds the next moment whose minute, hour, day, month and weekday all match the expression.
Can I use steps and ranges?
Yes. Fields accept asterisks, single values, comma lists (1,15,30), ranges (9-17), step values (*/5) and range-plus-step (1-30/5).
What presets can I choose?
Quick presets include every minute, every 5 and 15 minutes, hourly, daily at a time, weekdays, and first of the month.
Is it free to use?
Yes, free and unlimited with no signup required.
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