This cron expression explainer translates a five-field crontab schedule into plain English and shows exactly when it will fire next. Paste an expression like 0 9 * * 1-5 and instantly read a clear description plus the upcoming run times in your local timezone. Acting as a cron schedule parser and syntax checker, it validates every field, flags out-of-range or malformed input, and fully supports ranges, lists, and step values. It is built for developers, DevOps engineers, and QA testers who write or review cron jobs and want to confirm a schedule does what they intended before shipping it. Quick presets such as every 5 minutes or monthly help you build common schedules fast. Everything runs entirely in your browser, so your expressions are processed locally and nothing is uploaded to a server.
Features
Decodes all five cron fields (minute, hour, day-of-month, month, day-of-week) into a plain-language sentence
Previews the next six run times rendered in your local timezone
Supports ranges (1-5), lists (1,3,5), and step values (*/5)
Validates input and reports out-of-range or malformed fields with a clear error
One-click presets for common schedules like hourly, 9am daily, and weekdays
Handles day-of-month and day-of-week interplay using standard cron OR logic
Live updates as you type, no run button required
Runs entirely in your browser
How to use the Cron Explainer
Type or paste a five-field cron expression into the input box.
Or click a preset chip such as */5 * * * * to load a common schedule.
Read the plain-language description shown in the info banner.
Review the Next runs list to confirm the upcoming times in your local timezone.
Example
Input
0 9 * * 1-5
Output
Runs at minute 0, past hour 9, on every day-of-month, in every month, on Mon, Tue, Wed, Thu, Fri.
A weekday 9am schedule decoded into plain language.
Common errors & troubleshooting
Entering six fields with a seconds value at the start. — Use the standard five-field format (minute hour day-of-month month day-of-week); drop the seconds field.
A field value is rejected as out of range, like 60 for minutes or 13 for month. — Keep values within bounds: minute 0-59, hour 0-23, day-of-month 1-31, month 1-12, day-of-week 0-7.
Expecting both day-of-month and day-of-week to be required together. — When both fields are restricted, cron runs if either matches (OR logic), so the job may fire more often than expected.
Expected run times not appearing for a rare schedule. — The preview looks ahead one year; if no run falls in that window it reports none, so verify the day and month combination is reachable.
Frequently asked questions
What is the Cron Expression Explainer?
It is a browser tool that turns a standard five-field crontab schedule into a plain-English description and previews the next times the job will run.
What cron format does the explainer support?
Standard five fields — minute, hour, day-of-month, month, and day-of-week — with ranges, lists, and step values.
How do I check when my cron job runs next?
Paste your expression and read the Next runs list; the explainer calculates the upcoming run times in your device's local timezone.
How does it handle the day-of-month and day-of-week fields together?
It follows standard cron behavior: when both fields are restricted the job runs if either one matches, otherwise the restricted field applies.
Can I use step values like */15 or ranges like 1-5?
Yes, the explainer accepts steps, ranges, and comma-separated lists in any field and reflects them in the description and run preview.
Are my cron expressions sent anywhere when I use this tool?
No, the cron expression explainer parses everything locally in your browser and your input never leaves your device.