Cron Expression Builder NZ
This tool builds a cron expression from simple, plain-English choices, so you can create a schedule without memorising the cryptic syntax. Cron is the time-based scheduler used across Unix and Linux systems and countless tools to run jobs automatically, but its five-field format, with asterisks, slashes and ranges, is notoriously hard to write from scratch. Most people know what they want, run this every day at 9am, or every Monday morning, but translating that into the correct cron string is fiddly and error-prone. This builder reverses the problem: you describe the schedule and it writes the cron for you. You choose how often the job should run, daily, weekly, monthly, hourly or every few minutes, then set the relevant details such as the time of day, the day of the week, or the day of the month, and the calculator assembles the correct five-field cron expression and shows a plain-English description to confirm it does what you intend. The results update as you change the options. Use it to create a schedule for a cron job, to learn the syntax by seeing how choices map to fields, or to avoid the mistakes that come from hand-writing cron. The five fields are minute, hour, day of the month, month and day of the week, and the builder fills each according to your selections, using an asterisk for any field that should match every value. For example, a daily 9am job fixes the minute and hour and leaves the rest as wildcards, while a weekly job also fixes the day of the week. Once built, copy the expression straight into your crontab or scheduler. This pairs with the cron explainer, which goes the other way, translating an existing expression into plain English, and with the next-run tool that lists upcoming run times.
Builds a 5-field cron: minute hour day-of-month month day-of-week. For 'Every N minutes', enter N in the minute field. Copy the result into your crontab.
How it works
Based on how often you choose, the builder fixes the relevant fields and leaves the rest as wildcards. A daily schedule sets the minute and hour; a weekly one also sets the day of the week; a monthly one sets the day of the month; hourly fixes only the minute; and every N minutes uses a step in the minute field. The five fields are then assembled into the cron expression.
Worked example
Choosing a daily schedule at hour 9 and minute 0 produces the cron expression 0 9 * * *, meaning at 09:00 every day, with asterisks for day-of-month, month and day-of-week. Switching to weekly and selecting Monday would give 0 9 * * 1, running at 09:00 each Monday.
Related calculators
- Cron Explainer: cron to English.
- Cron Next Run: upcoming runs.
- Unix Timestamp: epoch time.
- Time Calculator: add and subtract time.