Cron Expression Builder
Build and explain cron expressions with a live human-readable preview.
* * * * *
Every minute of every day
Presets
Syntax reference
*any value5exact value1,2,5list of values1-5inclusive range*/15every 15 units
Build cron expressions without the cheat sheet
Cron is the world’s oldest job scheduler — a tiny language that has survived decades because it is universal, compact and unambiguous. But the syntax is terse enough that most people reach for a reference every time they write one. This builder lets you fill in each field, see a live preview, and pick from common presets.
The five fields
minute hour day-of-month month day-of-week
* * * * *
0-59 0-23 1-31 1-12 0-6 (Sun=0)Syntax cheatsheet
*— any value.5— this exact value.1,3,5— a list of values.1-5— an inclusive range.*/15— every 15 units.1-5/2— every second value from 1 through 5.
When cron beats alternatives
- Simple time-based schedules — “every Monday at 9am”, “first of the month”.
- Systems without a scheduler service — cron is available on every Unix-like OS.
- CI / automation runners — GitHub Actions, GitLab pipelines, Kubernetes CronJobs all accept cron expressions.
When you need anything dynamic (schedule based on state, retries, dependencies), reach for a proper workflow scheduler instead.
Frequently asked questions
- Which cron flavor is this?
- Standard 5-field Unix cron (minute, hour, day-of-month, month, day-of-week). Some systems (like AWS CloudWatch Events or Quartz) add a seconds field and a year field — this builder produces the widely-supported 5-field format.
- What is the difference between day-of-month and day-of-week?
- They look similar but combine as an OR, not an AND. `0 9 15 * 1` runs at 9am on the 15th of every month AND also on every Monday. Leave one as `*` if you only want to constrain the other.
- Can I use @yearly, @daily or @hourly shortcuts?
- Many cron implementations (Vixie cron on Linux, anacron, GitHub Actions, Kubernetes CronJobs) accept shortcuts like `@daily`, `@hourly`, `@weekly`. Those are shorthand for the standard 5-field expressions — the builder outputs the expanded form for maximum portability.