Impossible to tell. To many variables, and not all square footage is equal, all making square foot price a very poor metric.

Any idea what the cost would be for tjat plan?

Take the cost of a similar existing home (one level, same square footage with foundation and roof, similar finishes inside) and multiply that by 1.3 and you'll get a very big ballpark of what it will cost you to build, not including the lot. Or take a new tract home of a similar design and multiply that by 1.2 and you'll be in a similar (large) ballpark.

If you are far away from building supply stores or if there aren't a lot of builders in your area, it will be higher.

If you plan on doing any of it yourself, it will be lower.

If you need septic or well, it will be higher.

If utility connections are already there, it will be lower.

If you want gold plated appliances, it will be higher.

If you are fine walking around on plywood, it will be lower.

Bottom line, no one can tell you. Go talk to builders in your area and show them what you want generally for finishes and you'll get a better ballpark from them.

And all rules of thumb have been thrown out of whack by impacts of the pandemic and demand for builders as more people work from home and want to renovate their spaces.

Start interveiwing builders and get real quotes.

What do you like about that plan?

$300 - $1000+ sq. ft depending on location in the state, land costs and finishes.

In NY, its $450+ per sq ft. but all depends on your finishes, floor plan, materials etc

About 1.5X the cost of a very similar, recently newly built spec house in the same town in my experience in MA. Probably $400-600/sf with typical finishes.

Do you own the land yet? Our land was very expensive in MA. Depending where you are I would be happy to recommend our builder, he is in Southeast MA and we are building in central MA. https://www.visioncd.net/ He could give you a basic quote.

The cost would vary by town and the nature of the site and whatever you're told you won't know for sure until you have a complete design that can be priced.

You should plan on buying the $2,300 CAD files and you could give the seller $45 and your zip code to get a cost estimate for building the design. It might not be accurate but it'll be better than guessing at s.f. prices. I suspect it might not have a basement or a useful attic which is common in MA.

So, where will it be and do you have a lot?