Cron Expression Explainer
Translate any cron expression into plain English instantly. Supports 5-field and 6-field formats.
│ ┌─ hour (0–23)
│ │ ┌─ day of month (1–31)
│ │ │ ┌─ month (1–12 or JAN–DEC)
│ │ │ │ ┌─ day of week (0–7 or SUN–SAT; 0 and 7=Sunday)
│ │ │ │ │
* * * * *
Pure browser JavaScript — no external libraries.
How to use this tool
- Enter a cron expression (e.g. 0 9 * * 1-5).
- The human-readable description updates instantly.
- Use the field reference at the bottom as a reminder.
Translate any cron expression into plain English instantly. Supports 5-field and 6-field formats.
How it works
A cron expression is a compact string of 5 or 6 space-separated fields that defines a recurring schedule for a task. Reading cron syntax requires memorising the field order (minute, hour, day-of-month, month, day-of-week) and the meaning of special characters like *, /, comma, and hyphen. This tool translates any cron expression into plain English instantly.
Paste a cron expression (5 or 6 fields) into the input and the tool produces a human-readable description such as 'Every day at 2:30 AM' or 'Every 15 minutes, Monday through Friday.' This is useful when reviewing scheduled jobs in a crontab, CI pipeline, or cloud scheduler.
The tool supports standard 5-field cron (minute hour day month weekday) and 6-field extensions that add a seconds field at the start (used by some frameworks like Spring and AWS EventBridge).
For common special values: * means any value, */n means every nth unit, a-b means a range from a to b, and a,b,c means specific values a, b, and c.
Worked example
Understand a deployment pipeline schedule
- You see the cron expression '0 3 * * 1-5' in a CI config file.
- Paste it into the Cron Explainer input.
- The tool outputs: At 03:00, Monday through Friday.
- You now know the pipeline runs at 3 AM on every weekday.
Plain-English output: At 03:00, Monday through Friday.
Common mistakes to avoid
- Swapping the day-of-week field (0=Sunday in most cron implementations) -- some systems use 0=Monday, which can cause schedules to run on the wrong day.
- Using '0 0 30 2 *' (30th of February) -- this date never exists, so the job never runs.
- Forgetting that cron times are in the server's local timezone -- account for the UTC offset if your server runs in UTC but you want a local time.
Key terms
- Cron
- A time-based job scheduler in Unix-like systems. Jobs defined in a crontab file run automatically at the specified times.
- Cron expression
- A string of 5 or 6 fields specifying minute, hour, day-of-month, month, and day-of-week (plus optionally seconds) for a recurring schedule.
- Step value (*/n)
- In a cron field, */n means every nth unit. For example, */15 in the minute field means every 15 minutes.
Frequently asked questions
- What is 6-field cron?
- Some schedulers add a seconds field as the first field. This tool auto-detects and skips it.