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Cron Expression Parser

Every day 12:00
Every 5 minutes
1st of every month
Weekdays 9-18

Online Cron expression parser that computes the next execution times. Runs entirely in the browser.

How to Use & FAQ5 steps · 8 Q&A

Cron Expression Parser

Online Cron expression parser that computes the next execution times. Runs entirely in the browser.

How to Use

  1. Enter a Cron expressionType a 5-field expression, or click an example below to fill it in and then tweak it.
  2. Click "Parse"See the meaning and semantic description of each field to confirm your understanding.
  3. Check the next execution timesThe tool lists the next few execution times so you can confirm the expression behaves as expected.
  4. Check day/month vs weekday conflictsIf both day-of-month and weekday are set, remember the standard OR semantics; change one to a question mark if needed.
  5. Confirm against the target timezoneCompare the expression with the server timezone to avoid "correct locally but wrong in production".

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Related reading

Unix Timestamps 101: Seconds vs Milliseconds, UTC and TimezonesCron Expressions Explained: 5 vs 6 Fields and Pitfalls

FAQ

How do I read a Cron expression?

A standard Cron expression has 5 fields: minute, hour, day, month and weekday. This tool parses each field and computes the next and subsequent execution times so you can confirm the expression really behaves as intended.

Why is my Cron not firing as expected?

A common cause is misreading the field order or special symbols (* , - /), e.g. pinning both day-of-month and day-of-week so it triggers on OR. Use this tool to preview the next execution time and verify.

Does it support second-level Cron?

A standard 5-field Cron has no seconds field. If your system (e.g. some Spring, Quartz or cloud-function schedulers) supports 6-field (including seconds) expressions, follow the target platform docs; this tool parses the common 5-field form.

What do * ? / , - mean in an expression?

An asterisk means any value; a question mark means unspecified (used for day or weekday to avoid conflict); a slash is a step (e.g. */15 = every 15 minutes); a comma is a list (e.g. 1,15,30); a hyphen is a range (e.g. 9-18).

Can day-of-month and day-of-week be set at the same time?

Yes, but by standard behavior they are usually combined with OR, which can surprise you (writing both the 1st and Monday means "the 1st OR every Monday"). It is better to specify only one and use a question mark for the other.

Why do the computed times differ from my server?

This tool computes in the timezone of your browser, while servers often use UTC or a configured timezone. Confirm the target environment's timezone and interpret or convert the expression accordingly.

What are some common expression examples?

Daily at midnight: 0 0 * * *; every 30 minutes: */30 * * * *; weekdays at 9am: 0 9 * * 1-5; first of each month at midnight: 0 0 1 * *. Clickable examples are also provided below.

Can ranges, steps and lists be combined?

Yes. For example "every hour on weekdays" is 0 * * * 1-5; "every 10 minutes, only 8am–6pm" is */10 8-18 * * *. When combining, first picture which values satisfy the rule, then build the symbols.