Let’s talk about Challenge Levels (CL) in Swords & Wizardry. From a prepared monster perspective, they tell you whether or not they should pose a challenge to a party of a particular level. If you’re using the information on monster building, you can easily take a known monster and make it more (or less) difficult. Either way, the rulebook provides an easy way to manipulate the adventure.
If you’re converting from one system to Swords & Wizardry, you may want to add another perspective. I like to think of CL as a budget for buying powers and characteristics that I want to add to the monster. The relationship between Swords & Wizardry’s Challenge Level and Pathfinder’s Challenge Rating (CR) is linear. As you will see below, there is a little variability but you can almost use the same number for each.
The correlation between the two is r = .96 which is pretty substantial. Of course, I wouldn’t assume that there would be much variation here. Even when I tried other fit lines, they stayed linear. The increased variability at the high end may be due to the fact that there just aren’t a lot of super-powered monsters.
So, don’t be afraid to just take that CR5 Pathfinder monster and make him a CL5 Swords & Wizardry monster. It won’t make a huge difference in the end. Use the monster creation rules as listed to choose enough characteristics that will merit this challenge level. Next, we will try to tackle Armor Class. It’s a doozy. Happy converting!