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Cron Expression Explainer and Next Run Preview

Use this cron expression explainer to review scheduled jobs, automation rules, deployment checks, cleanup tasks, and recurring reports before saving a cron schedule.

Live developer utility

Cron expression explainer

Next run preview
Thursday 2026-06-04 09:15 local time
Thursday 2026-06-04 09:30 local time
Thursday 2026-06-04 09:45 local time
Thursday 2026-06-04 10:00 local time
Thursday 2026-06-04 10:15 local time
Schedule summary8 runs

Every 15 minutes during 09 through 17 on Monday through Friday.

Preview basisLocal

Showing up to 8 upcoming runs within 732 days.

Next runs

The preview starts after the selected start time. A run exactly equal to the start time is not included.

#WeekdayScheduled timeISO timestamp
1Thursday2026-06-04 09:15 local time2026-06-04T09:15:00.000Z
2Thursday2026-06-04 09:30 local time2026-06-04T09:30:00.000Z
3Thursday2026-06-04 09:45 local time2026-06-04T09:45:00.000Z
4Thursday2026-06-04 10:00 local time2026-06-04T10:00:00.000Z
5Thursday2026-06-04 10:15 local time2026-06-04T10:15:00.000Z
6Thursday2026-06-04 10:30 local time2026-06-04T10:30:00.000Z
7Thursday2026-06-04 10:45 local time2026-06-04T10:45:00.000Z
8Thursday2026-06-04 11:00 local time2026-06-04T11:00:00.000Z
Field breakdown

This page explains standard five-field cron: minute, hour, day of month, month, and day of week.

FieldExpressionValuesMeaning
Minute*/1500, 15, 30, 45Every 15 minutes
Hour9-1709, 10, 11, 12, 13, 14, 15, 16, 1709 through 17
Day of month*1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31Every day
Month*January, February, March, April, May, June, July, August, September, October, November, DecemberEvery month
Day of weekMON-FRIMonday, Tuesday, Wednesday, Thursday, FridayMonday through Friday
Warnings and assumptions
Review note
This explainer supports standard five-field cron expressions: minute hour day-of-month month day-of-week.
Local-time previews can shift around daylight saving time changes.
Dialect note

This tool supports common five-field cron syntax with wildcards, lists, ranges, steps, month names, and weekday names. It does not model seconds, years, Quartz tokens, Jenkins H, L, W, #, or ? modifiers.

Generation method

Cron preview method

Next runs = parse five cron fields + expand wildcards, lists, ranges, steps, month names, and weekday names + match future minutes against minute, hour, month, and day rules

This explainer supports standard five-field cron syntax. It does not model seconds, years, Quartz modifiers, Jenkins H, L, W, #, or ? tokens.

How to use

Steps

  1. Paste a five-field cron expression in minute hour day-of-month month day-of-week order.
  2. Choose whether the preview should use browser local time or UTC.
  3. Set the start-after time or use the current time.
  4. Review the field breakdown, next run preview, and warnings before saving the schedule in a real scheduler.

Example

Sample output

Weekday schedule*/15 9-17 * * MON-FRI
MeaningEvery 15 minutes during hours 09 through 17 on Monday through Friday
OutputField meanings, upcoming run times, timezone basis, and dialect warnings

Generator use

Best for

  • Browser-side link, file, format, and web utility tasks that need an output now.
  • Generating reusable artifacts such as QR codes, snippets, exports, or cleaned payloads.

Before relying on it

Check first

  • This explainer supports standard five-field cron syntax. It does not model seconds, years, Quartz modifiers, Jenkins H, L, W, #, or ? tokens.
  • Publishing a generated file or code without testing it in the real destination.
  • Encoding private or sensitive data into an output that other people can scan, copy, or inspect.

Details

What to know before using the output

Syntax scopeFive fields

The supported field order is minute, hour, day of month, month, and day of week.

Supported tokens*, lists, ranges, steps

Month names such as JAN and weekday names such as MON-FRI are supported alongside numeric fields.

Preview basisLocal time or UTC

The preview can use browser local time or UTC, but the real scheduler may use a configured server timezone.

Source notes

References used for this generator

man7.orgDocuments crontab field order, ranges, lists, steps, names, and day-of-month/day-of-week matching behavior.The Open GroupDocuments POSIX crontab utility behavior and the five time-and-date fields used by standard cron entries.

Benchmarks

How to read the output

Every minute: * * * * *.

Very frequent schedules can create load quickly; use sparingly for production jobs.

Hourly: 0 * * * *.

A common pattern for recurring syncs, checks, and cleanup tasks.

Weekday business hours: */15 9-17 * * MON-FRI.

Useful for jobs that should run during a human operating window rather than overnight.

Method and limitations

Methodology and assumptions

Formula, inputs, limitations and review record
Generation method

Next runs = parse five cron fields + expand wildcards, lists, ranges, steps, month names, and weekday names + match future minutes against minute, hour, month, and day rules

Inputs used

Cron expression, Start after, Preview time, Minute field, Hour field, Day fields

Limitations

Utility outputs depend on the encoded payload, file format, target app, scanner, printer, browser, and real-world testing before sharing.

Review record

Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.

Cite this page

Toolkit Shelf. Cron Expression Explainer and Next Run Preview. https://toolkitshelf.com/tools/cron-expression-explainer

FAQ

Common questions

Does this support six-field cron with seconds?

No. This tool explains standard five-field cron expressions. Some schedulers add seconds, years, or provider-specific modifiers that should be checked in that scheduler's own documentation.

Which timezone does the preview use?

You can preview with browser local time or UTC. Real schedulers may use server time, account time, project time, or a configured timezone, so check the scheduler before saving.

What happens when day-of-month and day-of-week are both restricted?

This preview follows common POSIX-style OR matching: a date can match either the day-of-month rule or the day-of-week rule. Some schedulers differ, so review warnings for those schedules.