Developer Tool

Crontab Builder & Decoder

Build cron expressions visually or decode any cron — plain-English explanation + next 10 run times. Supports Unix, Vercel, GitHub Actions, Kubernetes.

✅ Free Forever 🔒 No Signup ⚡ Instant Results 🌐 Browser Based

Quick Answer

The Crontab Builder is a free, browser-based cron expression parser and generator. Paste any 5-field cron (minute hour day-of-month month day-of-week) — see a plain-English explanation, validate every field, and preview the next 10 run times. Compatible with Unix cron, Vercel, GitHub Actions, AWS EventBridge and Kubernetes CronJobs.

Minute (0–59)

Hour (0–23)

Day of Month (1–31)

Month (1–12)

Day of Week (0–6)

1-5

Weekdays at 08:30 UTC

Next 10 runs (UTC)

2026-05-21 08:30:00(in 20 hr)
2026-05-22 08:30:00(in 2 days)
2026-05-25 08:30:00(in 5 days)
2026-05-26 08:30:00(in 6 days)
2026-05-27 08:30:00(in 7 days)
2026-05-28 08:30:00(in 8 days)
2026-05-29 08:30:00(in 9 days)
2026-06-01 08:30:00(in 12 days)
2026-06-02 08:30:00(in 13 days)
2026-06-03 08:30:00(in 14 days)

Quick Facts

Tool Name: Crontab Builder & Decoder
Category: Developer Tool
Price: ✓ Free
Platform: Browser Based
Login Required: ✓ No
Last updated: 2026-05-20

How to Use Crontab Builder & Decoder

Enter Your Input
Paste your text or fill in the required fields in the tool above.
Click Generate
Hit the generate or analyze button to start processing.
Get Instant Results
The tool processes your input instantly in your browser.
Copy or Export
Copy your results to clipboard or download the output.

Frequently Asked Questions

Everything you need to know about Crontab Builder & Decoder

What's the difference between Unix cron, Quartz and Kubernetes cron?

All three use the same five-field format (minute, hour, day-of-month, month, day-of-week). Quartz adds a 6th 'seconds' field at the front and a 7th 'year' field at the end. Kubernetes uses standard 5-field Unix cron in CronJob resources. This tool generates the Unix/Kubernetes-compatible 5-field format.

Why is day-of-week sometimes 0–6 and sometimes 1–7?

Traditional Unix cron uses 0–6 with 0 = Sunday. Some implementations (Quartz) use 1–7 with 1 = Sunday. Most Linux systems also accept both 0 and 7 for Sunday. We use the Unix convention (0 = Sunday).

How does the 'next 10 runs' calculation work?

We parse each field into a set of allowed values, then walk forward minute-by-minute from now, checking each candidate against all five constraints. Up to ~4 years of search per generation. All times are shown in UTC.

Can I generate Vercel / GitHub Actions / Cloudflare cron expressions?

Yes — they all use standard 5-field Unix cron. Vercel Cron Jobs, GitHub Actions schedule triggers, Cloudflare Worker scheduled triggers, AWS EventBridge (with the day-of-month / day-of-week '?' alternative) and Kubernetes CronJobs all accept the format this tool produces.

Are my expressions sent to a server?

No. Parsing, validation, plain-English description and next-run calculation all run in your browser. Safe for proprietary scheduling logic.

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