Cron Expression Parser & Builder
Parse cron expressions into plain English and build new ones visually.
What is Cron?
A two-way cron utility. Paste an expression like '0 9 * * 1-5' to see it explained in English, or assemble a schedule from selects and get the expression.
How it works
A small parser splits the 5 fields (minute, hour, day of month, month, day of week), expands ranges/lists/steps, and maps numeric values to names.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Weekday every 15 minutes
*/15 9-17 * * 1-5 parses to "every 15 minutes, 9am to 5pm, Monday to Friday" — the classic work-hours schedule.
Common mistakes
Timezone assumptions
Cron expressions run in the server's timezone, not the viewer's. A 0 9 * * * job fires at 9am server time wherever the server lives.
Five-field vs six-field
Some systems add a leading seconds field. The builder shows which variant you're editing so the expression ports cleanly.
Frequently asked questions
What does each field mean?
The five standard fields are minute, hour, day-of-month, month, and day-of-week. Ranges, lists, steps, and names are all supported.
How do day-of-month and day-of-week interact?
When both are specified, most implementations match if either matches. The parser explains the effective schedule so there are no surprises.
Can I build an expression visually?
Yes — select minutes, hours, and weekdays and the builder generates the matching expression and the next run times.