Cron syntax quick reference
A cron expression has five space-separated fields, evaluated left to right:
| Field | Values | Example |
|---|---|---|
| Minute | 0–59 | */15 * * * * — every 15 minutes |
| Hour | 0–23 | 0 2 * * * — daily at 02:00 |
| Day of month | 1–31 | 0 0 1 * * — first day of every month |
| Month | 1–12 or jan–dec | 0 9 1 6 * — June 1st at 09:00 |
| Day of week | 0–7 or sun–sat | 0 9 * * 1-5 — weekdays at 09:00 |
Frequently asked questions
What is a cron expression?
A cron expression is a five-field schedule (minute, hour, day of month, month, day of week) used by Unix/Linux's cron daemon to run a command automatically at fixed times, dates, or intervals — for example */5 * * * * runs a job every 5 minutes.
How do I read the timeline?
Each row is one job from your crontab; each dot is one time it actually runs. Scroll or pinch to zoom from minutes to weeks, drag to pan, and click a job's row, dot, or density bar to focus on just that job.
Does my crontab get uploaded anywhere?
No. Everything — parsing, scheduling math, and rendering — runs locally in your browser. The crontab text is kept only in your browser's localStorage; it is never sent to a server.
What crontab syntax is supported?
Standard 5-field Vixie cron: lists (1,15), ranges (1-5), steps (*/15), month and weekday names (jan-dec, sun-sat), wrap-around ranges (fri-mon), the @yearly…@hourly and @reboot shortcuts, and the /etc/crontab user field. Quartz-only tokens (L, W, #) aren't supported.
How is this different from crontab.guru?
crontab.guru describes one expression at a time in plain English. Cron Timeline is built for whole crontabs: paste every job you have and see them all plotted together on one zoomable timeline, so overlaps, gaps, and busy periods are visible at a glance instead of read one line at a time.
Is this free, and do I need an account?
Yes — it's free, with no account, no install, and no server component. Open the page, paste a crontab, and the timeline renders instantly.