Hi guys, I?m working on a project and find out that I had no idea about how much should I charge for the mere design of the application (requirements, use cases, diagrams). I think I have to charge something for the fact that i am spending a lot of time trying to architect things right eventhough the client won't see the results as fast as he expects (i?m not using an agile method), that is not a problem given that the software is for household use and the client is not familiar with any software process.
Anyway, what do you think would be a good method to calculate the price of the application and what would be a good percentage for design and for other development tasks.