Everyone wants to know but not everyone understands. The cost to build a home or an addition to a home is often quoted as a “cost per square foot.” You really need to know how that’s figured to understand the quote and understand what your final costs will be.As a home building coach and building industry advisor, I have the chance to answer a lot of home building questions. This is a popular one.Question: What does “building costs per square foot” really tell me?Answer:We hear a lot about the “cost per square foot” when it comes to home building. If you’re looking for the square footage cost of your project, you’re likely really wanting to know how to figure the entire project’s cost.But, what does “cost per square foot” really tell you?First, you must know what parts of the home or construction project are counted in the stated square footage of the structure. There’s a lot of confusion surrounding this. In most cases, what is being referred to is the actual enclosed living area or heated area of the home.Attached spaces (like porches), extra storage areas, workshops, etc. are typically not counted in the square footage of a home.Now, on to figuring the “Cost Per Square Foot.”When you’re quoted $100 per square foot (psf) to build your home, and you know the exact square footage, it becomes a simple matter of math.A two thousand square foot home, at $100 psf = $200,000 to build. This would be to build the entire home. And, since the foundation, garage, and attic are parts of the home … they are included in the $200,000.Just because they are not normally included in the square footage calculation, doesn’t mean that they won’t be built! The builder is, in essence, throwing them in for free … a better way to say it would be that they’re included in the quote of $100 psf. It’s just the way house projects are normally quoted.Ask For Details & Get it in WritingYou should never assume. Your area may be completely different. The builders you’re working with may have a different understanding and process. Always ask for clarification about what’s included and excluded. Don’t get caught short or confused. Get all the details before you decide on a builder, a materials package, or a project.Finally, get everything in writing. Then there won’t be any question.