Cron Expression Parser & Builder
Paste a cron expression to get a plain-English explanation and the next 10 run times, or build one visually field by field. All processing happens in your browser using your local time zone.
What is a Cron Expression?
A cron expression is a string of five fields used to schedule tasks to run automatically at specific times — minute, hour, day of month, month, and day of week. The cron daemon, found on virtually every Linux and Unix-like system, reads these expressions from a "crontab" file and executes the associated command when the schedule matches the current time. Cron expressions are also used in CI/CD pipelines (GitHub Actions, GitLab CI), Kubernetes CronJobs, and task schedulers across countless platforms.
This tool runs entirely in your browser — paste an expression to get an instant explanation, or build one visually field by field.
Cron Expression Format
A standard cron expression has five space-separated fields, in this order:
- Minute (0–59) — which minute of the hour the task should run.
- Hour (0–23) — which hour of the day, in 24-hour format.
- Day of month (1–31) — which day of the calendar month.
- Month (1–12 or JAN–DEC) — which month of the year.
- Day of week (0–6 or SUN–SAT, where 0 and 7 both mean Sunday) — which day of the week.
Each field can contain a specific value, a wildcard * (meaning "every"), a range (1-5), a list (1,15,30), or a step value (*/15 meaning "every 15 units").
How to Use This Tool
- Parse an expression — paste your cron string into the input field to see a plain-English explanation and the next 10 scheduled run times in your local time zone.
- Build visually — use the visual builder below to construct an expression field by field without memorising syntax.
- Use a preset — click any common schedule in the sidebar to load it instantly.
- Copy and deploy — copy the final expression and paste it into your crontab, GitHub Actions workflow, or Kubernetes CronJob spec.
Frequently Asked Questions
crontab -e to open your personal crontab in the default editor. Add a line in the format * * * * * /path/to/command. Save and exit — cron picks up the change automatically, no restart needed. Use crontab -l to list your current cron jobs.CRON_TZ variable in the crontab to set a specific time zone for individual jobs. GitHub Actions cron schedules always run in UTC regardless of your local setting.*), most cron implementations treat them as an OR — the job runs if EITHER condition is true. For example, 0 0 1,15 * 5 runs at midnight on the 1st, the 15th, AND every Friday. If you only want one condition, set the other field to * or use ? in systems that support it (like Quartz scheduler).systemctl status cron, (2) the script lacks execute permissions — run chmod +x script.sh, (3) the PATH environment variable is different in cron's minimal environment — use absolute paths to commands, (4) syntax errors in the crontab — check /var/log/syslog or /var/log/cron for errors, (5) the command outputs to stdout/stderr without redirection, causing mail delivery failures that mask the real error.schedule trigger using standard cron syntax: on: schedule: - cron: '0 9 * * 1-5'. Note that GitHub Actions schedules always run in UTC, and scheduled workflows may be delayed during periods of high load on GitHub's infrastructure — they are not guaranteed to run at the exact specified minute.