Cron Expression Generator

AI-powered

Turn plain English into cron expressions. Or paste a cron expression and get a human-readable explanation.

Cron expression

At 09:00, Monday through Friday

01 — Overview

How the Cron Expression Generator works

Convert natural language schedules into valid cron expressions and back. Supports 5-field standard and 6-field (with seconds) variants. Shows next 5 run times and an expanded explanation of every field.

02 — Use cases

When to use the Cron Expression Generator

  1. 01

    Schedule a backup every weekday at 2am

  2. 02

    Trigger a deploy on the first of the month

  3. 03

    Run a cleanup script every 15 minutes

  4. 04

    Translate an inherited cron expression to plain English before editing it

  5. 05

    Generate a cron string for GitHub Actions, Vercel Cron, or a Kubernetes CronJob

03 — Examples

Cron Expression Generator examples

every weekday at 9am

ex 01

0 9 * * 1-5

Runs at 9:00 AM on Monday through Friday.

every 15 minutes

ex 02

*/15 * * * *

Fires at minute 0, 15, 30, and 45 of every hour.

first day of every month at midnight

ex 03

0 0 1 * *

Useful for monthly billing or report jobs.

every sunday at 3:30am

ex 04

30 3 * * 0

Common weekly maintenance window.

twice an hour during business hours, monday to friday

ex 05

0,30 9-17 * * 1-5

Runs at :00 and :30 between 9am and 5pm on weekdays.

every 6 hours

ex 06

0 */6 * * *

Fires at 00:00, 06:00, 12:00, 18:00.

04 — FAQ

Cron — frequently asked questions

What does a cron expression look like?

A standard cron expression has five fields separated by spaces: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 are Sunday). Each field can be a number, a list (1,2,3), a range (1-5), a step (*/15), or a wildcard (*).

What's the difference between 5-field and 6-field cron?

5-field cron starts with the minute field and is the standard format used by Unix cron, GitHub Actions, and Vercel Cron. 6-field cron adds a leading seconds field and is used by Quartz scheduler, Spring, and some other systems. Pick the variant that matches the system you're scheduling on.

How do I run a job every X minutes?

Use a step value in the minute field: */5 for every 5 minutes, */15 for every 15 minutes. The first run is at minute 0 and then at each subsequent interval.

How do I write a cron expression for the last day of the month?

Standard cron doesn't have a native 'last day' token. Some implementations (Quartz, AWS) support L for last. With standard cron, the workaround is to run on every day from the 28th and have your script check whether it's actually the last day.

Does this work for GitHub Actions and Vercel Cron?

Yes. GitHub Actions and Vercel Cron both use standard 5-field POSIX cron. Generate a 5-field expression and paste it into your workflow file or vercel.ts schedule.

Can I get an expression for a specific timezone?

Cron expressions themselves don't carry timezone information — they're interpreted in the timezone of the system running them. Most schedulers default to UTC. Be explicit about timezone in your scheduler config, then write the expression in that timezone.

What does the 'next run times' preview mean?

After you generate or paste a cron expression, the tool computes the next five times the job would run if started right now, using your local timezone. Use this to sanity-check that the expression matches what you intended.

Why is my cron expression invalid?

The most common causes are: a value outside the allowed range (e.g. 60 in the minute field), a missing or extra field, or using day-of-week names in a scheduler that only accepts numbers. The validation panel will point to the offending field.

05 — Reference

Specs and further reading

The primary sources this tool follows. Where behaviour is defined by a specification, we link the specification rather than a summary of it.

  • POSIX crontab specification

    The Open Group — The normative definition of crontab behaviour that standard 5-field cron implementations follow.

  • crontab(5) manual page

    man7.org — Field-by-field reference for the crontab file format on Linux, including step and range syntax.

  • Vercel Cron Jobs

    Vercel — How 5-field expressions are interpreted by Vercel Cron, including its UTC-only timezone rule.

  • Events that trigger workflows

    GitHub — The schedule event, which accepts POSIX cron syntax and runs on UTC.

06 — Compare

How this compares to crontab.guru

Use crontab.guru when you already have a cron expression and need to know what it does — that's what it's built for. Use the generate.now cron tool when you have the schedule in words and need the syntax: it turns “every weekday at 9am” into 0 9 * * 1-5. Most people want both.

Read the full comparison→

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