BYTETOOLS

Cron Expression Parser

Parse a cron expression, read it in plain English and see the next 5 run times. Validates all five fields instantly — free, private and runs in your browser.

Fields: minute (0-59) · hour (0-23) · day-of-month (1-31) · month (1-12 / JAN-DEC) · day-of-week (0-6 / SUN-SAT).

What is the Cron Expression Parser?

The ByteTools Cron Expression Parser turns a cryptic five-field cron schedule into a clear plain-English sentence and shows you exactly when it will next run.

  • Plain-English description of any cron schedule
  • Next 5 run times computed in your local time zone
  • Supports wildcards, ranges, steps, lists and names (JAN-DEC, SUN-SAT)
  • Validates every field against its allowed range
  • Field-by-field breakdown for learning the syntax
  • 100% client-side — nothing is uploaded

How to use the Cron Expression Parser

  1. 1

    Enter a five-field cron expression (minute, hour, day-of-month, month, day-of-week).

  2. 2

    Click Parse cron.

  3. 3

    Read the plain-English summary of when the job runs.

  4. 4

    Review the field-by-field breakdown to see what each value means.

  5. 5

    Check the next five scheduled run times in your local time.

About the Cron Expression Parser

The ByteTools Cron Expression Parser turns a cryptic five-field cron schedule into a clear plain-English sentence and shows you exactly when it will next run. Paste an expression like 0 9 * * 1-5 and instantly learn it means every weekday at 9 in the morning.

It parses standard cron syntax — wildcards, ranges, steps, lists and month or weekday names — validates each field against its allowed range, and computes the next five run times in your local time zone. A field-by-field breakdown shows what each part means so you can learn the syntax as you go.

All parsing and scheduling maths happen locally in your browser. Nothing you enter is uploaded, so it is a safe, instant way to double-check a job schedule before you deploy it.

Frequently asked questions

What are the five fields in a cron expression?

In order they are minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), and day-of-week (0-6, where 0 is Sunday). A value, list, range, step or asterisk in each field controls when the job fires.

What does 0 9 * * 1-5 mean?

It means run at minute 0 of hour 9 — that is 9:00 AM — on every day-of-month, in every month, but only Monday through Friday. In plain English: every weekday at 9 AM.

How are the next run times calculated?

The parser starts from the current minute and steps forward, checking each minute against your schedule until it collects the next five matches. The calculation runs when you click Parse, using your device's local time zone.

How do day-of-month and day-of-week work together?

Following standard cron behaviour, if you restrict both the day-of-month and the day-of-week fields, the job runs when either one matches. If only one is restricted and the other is an asterisk, only the restricted field applies.

Does this support step and range values like */15 or 1-5?

Yes. You can use ranges (1-5), steps (*/15 or 0-30/10), lists (1,15,30) and combinations, plus three-letter month and weekday names such as JAN or MON. Each field is validated against its legal range.

Is my cron expression sent to a server?

No. Parsing, validation and the next-run calculations all happen in your browser, so your schedules stay private and the tool works even offline.

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