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Cron Visualizer Validator🔒 100% local
Visualize cron schedules. Privacy-first, no server uploads, no tracking.
Draws an expression as a grid of twenty-four rows, one per hour, with twelve columns of five minutes each and a # in every bucket that holds a run. Below the grid it prints the runs per day, the expanded minute, hour, day and month lists, and a note about which day rule is in force. All five fields are expanded locally, and the tool neither reads nor changes anything on your system.
How to use it
- Enter a five-field expression such as */15 9-17 * * 1-5.
- Press Process.
- Scan the rows for the hours that stay blank and read the When block underneath for the expanded values.
Worked example
*/15 9-17 * * 1-5becomesCron: */15 9-17 * * 1-5 (36 runs per day when active)
Minute grid (each column = 5 minutes, 00-59):
012345678901
00:00 ------------ (no run)
01:00 ------------ (no run)
02:00 ------------ (no run)
03:00 ------------ (no run)
04:00 ------------ (no run)
05:00 ------------ (no run)
06:00 ------------ (no run)
07:00 ------------ (no run)
08:00 ------------ (no run)
09:00 # # # # 4x
10:00 # # # # 4x
11:00 # # # # 4x
12:00 # # # # 4x
13:00 # # # # 4x
14:00 # # # # 4x
15:00 # # # # 4x
16:00 # # # # 4x
17:00 # # # # 4x
18:00 ------------ (no run)
19:00 ------------ (no run)
20:00 ------------ (no run)
21:00 ------------ (no run)
22:00 ------------ (no run)
23:00 ------------ (no run)
When:
Every: 4 minute(s) past — 0,15,30,45
Hours: 9, 10, 11, 12, 13, 14, 15, 16, 17
Days: every day | dow 1 Mon, 2 Tue, 3 Wed, 4 Thu, 5 Fri
Months: every month
Day-of-week activity:
1 Mon: 372 day slots
2 Tue: 372 day slots
3 Wed: 372 day slots
4 Thu: 372 day slots
5 Fri: 372 day slots
Only one day selector is restricted, so it acts as an AND with the month.
Reading the grid: rows are hours 00-23, columns are 5-minute buckets of that hour. A "#" means at least one run inside that 5-minute window.The 4x on each active row is the number of runs inside that hour. The day-slot figures under Day-of-week activity count calendar slots (31 days across 12 months), not actual working days.
When to use it
- You want to see at a glance whether a working-hours schedule really covers the hours you think it does.
- You are showing someone why 0 0 */2 * * is not every other day but the odd days of the month.
- You need the expanded minute and hour lists without setting up a crontab to watch.
What it does not do
- A bucket is marked whether it holds one run or two, so the grid shows where runs fall, not exactly how many.
- Exactly five fields are required. The six-field seconds form is refused with a field-count message.
- Numbers that fall outside a field's range are quietly dropped when the field is expanded, so a typo like 70-80 in the minutes column leaves a grid where every hour reads (no run) instead of raising an error.