Cron Syntax Guide

Cron syntax varies significantly between platforms. Select a dialect below to see its field structure, special characters, day-of-week numbering, aliases, and common gotchas.

Unix Cron

The original 5-field cron from Version 7 Unix — the lowest common denominator across POSIX systems.

5 fields: minute hour day-of-month month day-of-week

Vixie Cron

Paul Vixie's 1987 extended cron — the de facto Linux default, source of `@daily`, `*/n`, and named days.

5 fields: minute hour day-of-month month day-of-week

AWS EventBridge Cron

Amazon's 6-field cron for EventBridge Scheduler and CloudWatch Events — adds a year field, drops compatibility with `*`-in-both-day-fields.

6 fields: minute hour day-of-month month day-of-week year

GitHub Actions Cron

5-field POSIX-style cron for workflow `schedule` triggers — defaults to UTC (optional `timezone:` field since March 2026), 5-minute minimum interval.

5 fields: minute hour day-of-month month day-of-week

Kubernetes CronJob

5-field cron for `CronJob` resources — Vixie-style syntax (parsed by robfig/cron), plus a `timeZone` spec field since Kubernetes 1.25.

5 fields: minute hour day-of-month month day-of-week

Quartz Cron

Java's Quartz Scheduler — 6 or 7 fields, seconds resolution, `L`/`W`/`#` tokens, and 1-indexed day-of-week.

6 or 7 fields: second minute hour day-of-month month day-of-week [year]

Spring Cron

Spring Framework's `@Scheduled` cron — 6 fields (with seconds), Quartz-style L/W/# since Spring 5.3, and 0-indexed day-of-week like Unix.

6 fields: second minute hour day-of-month month day-of-week

Azure Functions (NCRONTAB)

6-field NCRONTAB format used by Azure Functions timer triggers — seconds first, day-of-week 0–6, full step syntax.

6 fields: second minute hour day-of-month month day-of-week

Not sure which syntax you need?

Paste any cron expression into the tester — it auto-detects POSIX, Quartz, and GitHub Actions syntax.

Open Cron Tester