⏰ Cron to Text: Crontab Expression Translator and Explainer

What is the Cron Expression to Text?

Cron is the time-based job scheduler built into Unix and Linux, and its cron to text syntax has become a de facto standard far beyond cron itself. CI pipelines, container orchestrators like Kubernetes, serverless platforms and many application frameworks all accept the same five-field expression. Reading one at a glance is hard, which is exactly what a cron to text translator solves: it converts the terse syntax into words a human can verify before trusting it in production. A standard expression has five fields separated by single spaces, in this fixed order: minute, hour, day-of-month, month, and day-of-week. The job runs whenever the current time matches every field at once.

Each field accepts four kinds of value, and understanding them is the core of reading any cron schedule. A single number means exactly that value, so 5 in the minute field means minute 5. A star () means every value the field allows. A comma-separated list means any of several values, so 1,15 in day-of-month means the 1st and the 15th. A hyphen range means a span, so 1-5 in day-of-week means Monday through Friday. On top of any of these you can add a step with a slash: /15 in the minute field means every 15 minutes, and 0-30/10 means minutes 0, 10, 20 and 30. Combine these across five fields and you can express almost any recurring schedule.

The field that trips people up most is day-of-week. It runs 0 to 6 where 0 is Sunday, and on many systems 7 is also accepted as Sunday. Most crons also accept three-letter names, so SUN, MON through SAT work in day-of-week and JAN through DEC work in the month field, which often reads more clearly than a number. The other subtle rule is how day-of-month and day-of-week interact: in classic cron, when both are restricted (neither is a star) the job runs when either one matches, not both. That surprises people who write 0 0 13 * 5 expecting Friday the 13th and instead get every 13th plus every Friday.

Some schedulers extend the basic syntax, and a good cron to text reading has to know the limits. Named macros are shorthand strings that start with an @ sign and replace all five fields: @daily and @midnight both mean 0 0 , @hourly means 0 , @weekly means 0 0 0, @monthly means 0 0 1 , @yearly and @annually mean 0 0 1 1 , and @reboot runs once when the system starts. Quartz and Spring style schedulers add a leading seconds field (making six fields) and special characters such as L for the last day, W for the nearest weekday, and # for the nth weekday of the month, as in 6#3 for the third Friday. AWS EventBridge uses its own six-field variant with a required year and a ? placeholder.

This tool focuses on the classic 5-field POSIX cron format because that is what most servers, crontabs and framework schedulers actually run. It parses numbers, stars, lists, ranges and steps and turns them into a clear description, so you can read a cron schedule with confidence, catch a mistake before you deploy, and document what a job really does. One caveat worth remembering across every scheduler: cron does not know your timezone unless you tell it, so a schedule that looks like 2am may fire in UTC or in the server clock, not your local time.

When to use it

• Double-checking a crontab line a colleague wrote before you deploy it to a production server.
• Documenting what a scheduled job does so the code comment matches the actual schedule.
• Learning cron syntax by typing an expression and reading the plain English it produces.
• Debugging a job that fires at the wrong time by inspecting the field-by-field breakdown.
• Reviewing a CI pipeline or Kubernetes CronJob schedule during a code review.
• Migrating jobs between servers and confirming each schedule survived the copy unchanged.

How to use the Cron Expression to Text

1. Type or paste a 5-field cron expression into the box, in the order minute hour day-of-month month day-of-week.
2. Read the plain English description that appears instantly above the table.
3. Check the field-by-field breakdown to confirm each part means what you expect.
4. Use a preset button as a starting point, then edit it to match the schedule you need.
5. Copy the description into your crontab as a comment so the next person can read the schedule at a glance.

Formula & method

Worked examples

The five cron fields, in order, with their allowed values

Special characters you can use in a field

Common cron expressions and what they mean

Common mistakes to avoid

• Getting the field order wrong. The order is minute, hour, day-of-month, month, day-of-week. Putting the hour first (a habit from reading clocks) means the job fires at the wrong minute. Read the breakdown table to confirm each field landed where you intended.
• Assuming Sunday is 7. The standard range for day-of-week is 0 to 6 with 0 as Sunday. Many systems also accept 7 as Sunday, but not all do, so 0 is the safe choice for Sunday across schedulers.
• Mixing up day-of-month and day-of-week. When both day fields are restricted (neither is a star), classic cron runs the job when either field matches, not both. So 0 0 13 * 5 is not Friday the 13th, it is every 13th and every Friday. If you mean a specific weekday, leave day-of-month as a star.
• Reading */15 as starting at 15. A step like */15 starts at the lowest allowed value, so in the minute field it fires at 0, 15, 30 and 45, not at 15, 30 and 45. To start later, use a range such as 15-59/15.
• Forgetting about timezone. Cron uses the server clock or UTC, not your local time, unless the scheduler is configured with a timezone. A job set for 2 may not run at 2am where you live. Check the server timezone before relying on an hour value.
• Assuming macros and L, W, # always work. Named strings like @daily and special characters L, W and # are not part of classic POSIX cron. They work in Quartz, Spring and some cloud schedulers but will error on a plain Unix crontab. Confirm your scheduler supports them before using them.

Glossary

Cron

The time-based job scheduler on Unix and Linux that runs commands at fixed times, dates or intervals.

Crontab

The configuration file (and command) that holds a user's cron jobs, one schedule plus command per line.

Field

One of the five space-separated parts of a cron expression: minute, hour, day-of-month, month or day-of-week.

Step value

A slash expression like */15 that matches every nth value across a range, for example every 15 minutes.

Range

A hyphen expression like 1-5 that matches every value from the start to the end inclusive.

Macro

A shorthand string starting with @ that replaces all five fields, such as @daily for 0 0 * * *.

Quartz cron

A six or seven field cron variant used by Java schedulers that adds a seconds field and special characters like L, W and #.

CronJob

A Kubernetes object that runs a containerized task on a cron schedule, using the same five-field syntax.

Frequently asked questions