Theoretically you want to charge right up to your client's "willingness to pay." If they think it's valuable enough to patent, they possibly are willing to pay

Theoretically you want to charge right up to your client's "willingness to pay." If they think it's valuable enough to patent, they possibly are willing to pay a lot for it. That's the argument for charging more. On the other hand, we don't know how unique your skills are. If they could easily replace you with another developer, they're not going to be willing to pay you much more than the going rate for your skills, no matter how valuable the end product may be to them. I forget how it works with patents, but doesn't the name of the actual creator (i.e. you) get listed on the patent, even if it is a contract job? A lawyer could confirm. Or check out the relevant Nolo Press book.