Cron Expression Parser

Parse cron expressions and see the next scheduled run times instantly — free cron checker.

Fields are minute, hour, day of month, month and day of week. Use *, */n, a-b, a-b/n and comma lists.

About

About the Cron Expression Parser

Reads a standard five-field cron expression and lists the next five times it would run, in UTC.

Backend developers and DevOps engineers use it to sanity-check a cron schedule before deploying it, since a small mistake in the fields can silently run a job at the wrong time or not at all. It's one of many free developer tools on Toolapt, and like every tool here, it's free to use with no sign-up and no limit on how many times you run it.

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Guide

Using the Cron Expression Parser

  1. 1

    Step 1

    Enter a five-field cron expression in the Cron expression field.

  2. 2

    Step 2

    Click "Parse".

  3. 3

    Step 3

    Read the next five run times, shown in UTC.

  4. 4

    Step 4

    Adjust the expression and re-parse until the schedule looks right.

  • Parses standard five-field cron expressions: minute, hour, day of month, month, day of week
  • Supports *, step values (*/15), ranges (9-17), range steps (9-17/2) and comma lists in every field
  • Lists the next five matching run times, computed from the current time in UTC
  • Correctly applies cron's OR rule when both day-of-month and day-of-week are restricted
  • Clear error messages when a field is out of range or the expression doesn't have five fields
  • Works entirely in your browser — nothing you enter is sent to a server
  • Free to use, with no sign-up and no limit on how many times you run it

Backend developers

Backend developers use the Cron Expression Parser for sanity-checking a scheduled job's expression before deploying it.

DevOps engineers

DevOps engineers use the Cron Expression Parser for verifying a maintenance window or backup schedule will actually fire when expected.

QA engineers

QA engineers use the Cron Expression Parser for confirming a scheduled task's timing matches what a ticket or spec describes.

Students learning cron

Students learning cron use the Cron Expression Parser for seeing exactly how each field and operator changes when a job runs.

Examples

Cron Expression Parser examples

3 worked examples

01

Parsing */15 9-17 * * 1-5

Parsing */15 9-17 * * 1-5 shows it firing every 15 minutes from 9am to 5pm, Monday through Friday — 36 runs on each weekday.

02

Parsing 0 0 * * 0

Parsing 0 0 * * 0 shows it firing once a week, at midnight every Sunday, since day-of-week 0 means Sunday.

03

The day-of-month/day-of-week OR rule

Parsing 0 9 1 * 1 shows it firing at 9am on the 1st of the month OR every Monday, since cron treats both restricted fields as an OR, not an AND.

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FAQ

Frequently asked questions

Quick answers to common questions about the Cron Expression Parser.

What does the Cron Expression Parser do?

It reads a five-field cron expression and shows the next five times it would actually run, in UTC.

Is the Cron Expression Parser free to use?

Yes. It's free, with no sign-up, no watermark and no limit on how many times you use it.

Is my cron expression safe when I use this tool?

Yes. Parsing happens entirely on your own device — nothing you enter is sent to a server.

What format does the expression need to be in?

Five space-separated fields, in order: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6, where 0 is Sunday).

What operators are supported in each field?

* for "every value", */n for a step, a-b for a range, a-b/n for a stepped range, and comma-separated lists combining any of the above.

Why are the run times shown in UTC instead of my local time?

Cron schedules are commonly defined and run in UTC on servers, so showing UTC avoids ambiguity about which time zone the schedule refers to.

What happens if I restrict both day-of-month and day-of-week?

Following standard cron behavior, the tool treats them as an OR: a day matches if it satisfies either field, not both — this is the same rule real cron implementations use.

Can I use this tool on my phone?

Yes. The page is fully responsive and works on mobile, tablet and desktop browsers alike.

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