UtilityBaseDeveloper Tools
Cron Expression Explainer
Type a cron expression and get plain English — '0 9 * * 1-5' explained instantly.
Updated July 7, 2026
How to use the cron expression explainer
- 1Type or paste the cron expression — the English translation updates live.
- 2Use the presets to start from a common schedule and modify it.
- 3Check the syntax table for what each symbol means.
- 4Confirm the English matches your intent before deploying, and mind the server's time zone.
Common uses
- Sanity-checking a crontab entry before it goes to production
- Decoding a cron schedule you found in an unfamiliar codebase or CI config
- Writing schedules for GitHub Actions, Vercel Cron, or Kubernetes CronJobs
- Learning cron syntax by editing presets and watching the English change
Frequently asked questions
What are the five fields?
In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12), day of week (0–6, Sunday = 0). '30 18 * * 5' reads: minute 30, hour 18, any day, any month, Friday — 6:30 PM Fridays.
What happens when day-of-month AND day-of-week are both set?
The classic gotcha: standard cron ORs them. '0 9 13 * 5' runs at 9 AM on the 13th AND on every Friday — not only Friday the 13th. If you need the intersection, put the second condition in the script itself.
How do steps like */15 work?
'Every Nth value': */15 in the minute field fires at :00, :15, :30, :45. Steps combine with ranges too — 9-17/2 in the hour field means every 2 hours from 9 AM through 5 PM.
Why did my job run at the wrong hour?
Time zones. Cron uses the host machine's zone, which on servers is usually UTC — so '0 9' means 9 AM UTC, not your local morning. Check the server's zone, and remember DST shifts can double-fire or skip jobs scheduled in local-time zones.
About this tool
The cron expression explainer translates crontab schedules into plain English as you type: 0 9 * * 1-5 becomes 'At 9:00 AM, on Monday through Friday.' It handles the full standard 5-field syntax — wildcards, exact values, ranges, steps (*/15), lists, and named months and weekdays — plus one-click presets for the schedules everyone actually writes. A built-in syntax reference decodes each symbol. Cron's terseness is its trap: the fields are easy to transpose, day-of-month and day-of-week interact in a way almost nobody remembers, and a mistake means a job silently running at 3 AM daily instead of monthly. Reading your expression back in English before deploying it is the cheap insurance.
Like everything on UtilityBase, the cron expression explainer runs entirely in your browser — nothing you enter is uploaded or stored on a server. It's free to use with no account required. Browse more developer tools here.
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