Go to https://ivofrolov.github.io/cronsheet/ and paste your crontab.
Or you can clone the repo and open index.html by hand. No server needed.
It provides overview of "busy" slots over a day.
Given a crontab
# m h dom mon dow user command
30 7 * * * user make coffee
* * * * * user fping localhost
5 * * * * root logrotate
and a grid granularity of 15 minutes, schedule will look something like this.
Command / Time, h. 00 01 02 03 04 05 06 07 08 09 10 11 12 ~ 23
make coffee ▒ ~
fping localhost ▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ~ ▒▒▒▒
logrotate ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ▒ ~ ▒
^
07:00 to 07:15 slot