Through my carrer Ive developed and used a percentage based formula for specific home projects, to help me properly frame homeowners budget expectations for a project during initial discussions. To help them not only prepare for any potential sticker shock, but to act as a guide, a map so to speak, for what is appropriate for the project and their home. Of course you can always chose to go above or below these guidelines, but it properly sets parameters for budget expectations for the project you are considering. I am pleased to see now, that leaders in the industries standards, adopting and utilizing this very method, and feel this is a big help for everyone involved in the home remodeling process.
The Appraisal Institute and the Houzz organization have put out a % based budget guideline for home improvements, based on the overall value of the home and the project being considered. This is a great guide for setting expectations for budget amounts accurately and realistically. Below are the guidelines listed along with a floorplan graphic. Of course this is just a guide, and costs for a job can be adjusted and determined by a host of factors.
I believe that by removing the obstacle of uncertainty and vagueness around and about price, when considering to do a project, will be a benefit and a valuable education for perspective remodeling customers. Allowing them to realistcally prepare, anticipate and decide, to undertake a home improvement project.
Kitchen Remodel = 10-15% of home value
Master Bath Remodel = 10% of home value
Guest Bath Remodel = 5% of home value
Finished Basement = 10-15% of home value
Decks & Patios = 2-5% of home value
Finished Attic = 10-15% of home value
Other Rooms = 1-3% of home value