# Are there rules for designing custom buildings for kingdom?

I have been looking into kingdom building rules for the sake of my newest game and I noticed that a lot of buildings have prices like 42 BP or 38 BP and that made me think that they were somehow made using a set of rules similar to how buildings are made using rooms as a basis. So what I want to ask is that are there any rules for designing custom kingdom buildings based on their effects and how many lots they occupy?

## No (and there's only a little bit of guidance)

There are no rules from Paizo for custom buildings. There is some guidance on what drives BP prices, but it's not enough to constitute rules for custom buildings:

Build points don’t have a precise exchange rate to gold pieces because they don’t represent exact amounts of specific resources. For example, you can’t really equate the productivity of a blacksmith with that of a stable, as their goods are used for different things and aren’t produced at the same rate, but both of them contribute to a kingdom’s overall economy. In general, 1 BP is worth approximately 4,000 gp; use this value to get a sense of how costly various kingdom expenditures are.

(source: Ultimate Campaign)

Upgrade To/From: Some buildings can be converted into a more advanced form of the existing building, such as converting a Shrine into a Temple. To upgrade a building, pay the BP cost difference between the current building and the new building. Remove the modifiers from the old building and apply the modifiers from the new building. Upgrading counts as constructing a building for the purpose of the maximum number of buildings you can construct on your turn. You can't upgrade a building to a larger one if there isn't space in the District Grid for the building's new size.

(source: Ultimate Campaign)

The closest you can get to deriving rules for custom buildings is to try to reverse-engineer the existing building prices, but that actually points to there not being a specific formula for it: this post and this post from the Paizo forums by bmcdaniel finds that there's no deterministic way to derive BP from the inputs. If Paizo used a formula, they massaged the results in a way that they have not defined in the rules, so any custom building will inherently be homebrew.

• have you considered the kingdom rules from Kingmaker? Commented Sep 27, 2022 at 14:17
• If you mean the campaign, it was released before Ultimate Campaign and (as far as I know) the UC rules are more comprehensive than the Kingmaker rules. If you mean the videogame, I'm not super familiar with it. Commented Sep 27, 2022 at 19:22
• I meant the campaign, because that offered some baseline about what a kingdom 'from scratch' would offer. Commented Sep 27, 2022 at 22:51