Explain 5-field cron expression in plain english

Cron Expression Parser is a professional tool that translates the cryptic * * * * * syntax into a clear Chinese or English description, so operations engineers and developers can quickly verify when a scheduled task will fire. Built on cronstrue, it supports the standard 5-field cron syntax as well as common second-level extensions.

Step 1 — type a cron expression such as */5 * * * * in the input box; the tool describes the schedule in natural language below it in real time. Step 2 — illegal expressions show a red error message with the exact offending field and reason. Step 3 — pick Chinese or English at the top for internationalised teams. Step 4 — the "Common presets" area offers the most common schedules (every minute, hourly, daily, weekly, monthly) that fill the input on click. Step 5 — the "Field reference" table at the bottom shows the meaning and value range of each of the five cron fields for reference.

Linux administrators sanity-check an expression before saving crontab -e; DevOps engineers configure GitLab CI Schedule or GitHub Actions cron triggers; Kubernetes CronJob resource definitions are validated; back-end developers verify schedules for Quartz, node-cron and similar frameworks; data platform engineers configure the schedule expression of an Airflow DAG.

Standard cron has 5 fields, from left to right: minute (0–59), hour (0–23), day (1–31), month (1–12), day-of-week (0–6, where 0 is Sunday). It supports * (any), / (step, e.g. */5), - (range, e.g. 1-5) and , (list, e.g. 1,3,5). Day-of-week also accepts three-letter names MON-SUN. Some implementations (like Quartz) support 6 fields (extra seconds) or 7 fields (extra year); the tool tries to recognise these too.

All parsing happens locally in your browser and the expression is never uploaded, so it is safe for validating cron configurations that contain internal system schedule information.