I am wondering how many domains or accounts can a server using cPanel/WHM host without being considered oversold?

I would like to provide an service that is considered quality, but I also want to use every bit of resource available the server can provide so I can maximise revenue.

cPanel/WHM doesn't have anything to do with the amount of accounts/domains you can host on the server. The server hardware and connection is what matters. It's obvious that a cheap Celeron server running cPanel won't be able to handle as much as a Dual CPU Quad Core Xeon with 8GB of RAM can handle.

Even if we know your server specifications, the answer would also depends on:
- The size of the accounts
- The kind of websites you're hosting (static pages, file hosting, simple dynamic applications, powerful ecommerce websites with a huge database backend, ...)
- The amount of simultaneous visitors
- ...

In other words: There is no right answer to your question.

I am wondering how many domains or accounts can a server using cPanel/WHM host without being considered oversold?

I would like to provide an service that is considered quality, but I also want to use every bit of resource available the server can provide so I can maximise revenue.

If you sell 5gb of space, deduct that from your total. So if you have a 500gb hard drive, only sell 100 5gb accounts, that would be not overselling.

However, as the previous post has said it's not as easy as that.

Ok, maybe I forgot to spec out my server. :)

It'll be a Dell PowerEdge 2950 with standard specifications.

2x Dual Core Xeon, 6MB Cache, 1.86GHz
8GB 667MHz RAM
2x 73GB Harddrive
Gigabit Ethernet NIC

Websites will be mostly dynamic with MySQL connections
Mostly moderate email usage.

sorry it's a off topic, but are you the guy behind hagenhosting?

Would cPanel be suitable for small free accounts? Regardless of bandwidth and hard drive usage, what kind of load per 100 accounts roughly would I be looking at?

The answer I posted earlier also applies to your question. Your load doesn't have anything to do with the AMOUNT of accounts but with your hardware, the type of the website, the amount of visitors the websites receive, the database back-end used by the websites...

Got a server with 150 accounts on it and server load is always under 0.05 and memory usage is under 10%, but this is quite a beefy server. Anyway it depends a lot on the accounts and server specs

That's one of the oldest questions in the book and there are so many factors that influence the number of sites a cPanel server (or any other server, for that matter) can house. Our license allows for unlimited users. The limiting factor is usually server hardware. The type of sites, caliber of hardware, and usage patterns of user accounts is what will ultimately determine how many sites a server can house.

There's really no hard & fast answer to the question.