Why Use This Tool
Cron syntax is notoriously cryptic. An explainer confirms your expression means what you think it does, preventing accidental scheduling errors that could trigger jobs at wrong times.
Cron Expression Explainer
Free online cron expression explainer. Paste any cron expression and get a plain English explanation of when it runs. Includes next run times. — runs 100% in your browser, client-side only. No data is sent to any server. Free to use, no account required.
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Client-Side
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How to Use the Cron Expression Explainer
- Enter a cron expression (5 fields: minute hour day month weekday).
- Click Explain to see a plain-English breakdown and the next 5 scheduled run times.
Supports *, */N, ranges (1-5), and lists (1,3,5).
What is Cron Expression Explainer?
A cron expression explainer parses cron syntax (like '0 9 * * 1') and translates it into human-readable descriptions. It shows when the schedule will trigger and validates the expression syntax.
When to Use It
Use a cron explainer when reviewing existing crontabs, validating scheduled tasks before deployment, understanding inherited cron configurations, or learning cron syntax.
Who Should Use It
On-call engineers, DevOps teams, and developers maintaining inherited schedulers.
How to Use the Cron Expression Explainer
- Paste cron expression
- Review plain-English schedule interpretation
- Confirm timezone/platform format
- Correct expression and retest before rollout
Security note
Validate timezone and DST assumptions to avoid off-hour or duplicate execution of sensitive jobs.
Common Uses
- Validating cron expressions before deployment
- Understanding inherited crontab configurations
- Learning cron syntax
Frequently Asked Questions
What does * mean in cron?
Asterisk means 'every' — every minute, every hour, etc. for that field. '* * * * *' runs every minute. '0 * * * *' runs at minute 0 of every hour.
What's the difference between / and ,?
/ means 'every N' (*/15 = every 15). Comma lists specific values (1,15 = on the 1st and 15th). Both can combine: '0,30 */2' means at :00 and :30 of every 2nd hour.
Why does my cron have 5 vs 6 fields?
Standard Unix cron uses 5 fields (minute to day-of-week). Some systems (Quartz, Spring) add a seconds field as field 1. Check your scheduler's documentation.