Crontab Explainer
Parse cron expressions, see breakdown, next 5 execution times, human explanation, common presets. Offline.
About this tool
Paste any cron expression (the 5-field Unix format) and see what each field means, a human-readable explanation, and the next 5 times the schedule would fire. The five fields are minute, hour, day of month, month, and day of week — each card shows the raw value, the resolved list (e.g. */15 becomes "0, 15, 30, 45"), and a one-line meaning. Common presets are listed as quick-tap buttons: every minute, every 15 minutes, every hour, daily at midnight, weekdays at 9 AM, and so on. Works fully offline.
Details
- Category
- developer
- Version
- 1.0.0
- Size
- 13 KB
- Updated
- Jun 2026
Frequently Asked Questions
What is the 5-field cron format?
Minute (0-59), Hour (0-23), Day of month (1-31), Month (1-12), Day of week (0-6, Sun=0 or 7). An asterisk means "every". A slash means step (*/15 = every 15). A dash means range (1-5). A comma means list. The fifth field is independent of the day-of-month field — if both are restricted, cron fires when either matches.
Why might "next 5 runs" give a far-future time?
When the day-of-month and day-of-week fields are both restricted, classic cron uses OR semantics — the schedule fires when either matches. So "0 0 1 * 1" fires on the 1st of every month AND every Monday. The next-5 calculation respects this. Some cron implementations (Quartz, modern systemd) use AND semantics instead.
Does this support seconds, year, or special strings like @daily?
No — only the classic 5-field Unix format. Quartz-style 6-field (with seconds) and 7-field (with year) are not supported. Special strings (@yearly, @monthly, @weekly, @daily, @hourly, @reboot) are not expanded.
Which time zone are the next-run times in?
Your browser local time. Cron is fundamentally timezone-naive — most systems run cron in the server timezone. Double-check which timezone your cron daemon actually uses before relying on the times shown.