I am installing canlights in the basement and need a clarification on how many wires I can have in the junction box. It states max 8 no. 12 wire 4 in 4 out through branch circuit conductors. I am using no 12 does this mean I can have a total of 8 wires in the box. I am using it to run to a couple outlets "easier layout" and there are 3 connectors to conduit then a total of 8 wires. The fill calculations seems like it is to many wires but the 8 total has me confused. I can reduce by 1 since the lights and outlets will be on the same breaker. This is just a large open room that will not require arc fault either. Thanks

Your post is a bit confusing, but I think I get what you are asking.

You can use the J-boxes for pretty much anything. It does not matter at all that you are mixing receptacles and lighting.

The "Max 8 #12" means just that. EACH insulated wire, hot or neutral, counts as ONE. ALL the grounds together count as one.
So... three 12/2's would be seven conductors; the max you can put in those boxes.

I would avoid junction box if possible, and wire from fixture to fixture(daisey chain). Eleminates a lot of problems. May use more wire.