Cost-to-build calculators that account for open split-level

One of my life goals is to design and build (er, mostly pay someone else to build) my own house. I think my finances are on track to make it doable around the time I retire or possibly even a little before, but I want to narrow the figure down a bit to get a firmer number of how much I need to save.

I have an idea of what kind of terrain I want the house on and in what part of the US, approximately how many square feet, and I've got some basic designs worked out on paper. I used to have them in Sketchup too until that became not free anymore.

The problem is, all the online calculators to figure out how much a home would cost to build seem to be based on traditional 1, 2, or 3+ story designs. My design is a tri-level that includes a lofted upstairs master suite that looks out onto the open below-grade walk-out living room, as does the ground-floor kitchen. I have no idea how to map that onto the conventional types of calculators.

Is there a calculator out there that is layman-friendly but also accounts for design oddities like this?

Or, is there a manual way to calculate the cost instead?

The calculators are really estimators and look at average finishes and material usage. I once had a high-end builder come out to give me a bid on an addition I wanted built. I had done a design on cad right down to the studs and I had everything spec-ed out in detail. He was just coming off a $12M home build and I was surprised he even wanted to look at my little project. He sat there a minute and said wow you are asking for a better build quality than the last place I built. I asked him how that was possible and how it is even possible to get the cost of a home that high. He told me it was easy when the buyer wanted some special marble from Italy and he required I send a stonecutter from here to Italy for a month to select every piece cut from the mountain. He said every surface in the home was like that, but the basic construction was just 2x4 and drywall etc.


I would suggest as you are in no hurry and planning your dream home, do a total design and itemize it all just as you want it. Then try and figure out what you think the labor should be along with the prevailing wage in your area and then likely double that.


If the eventual build will be down the road some years all this will be a moving target that will likely be going up.

I hear ya. I could use a decent estimate though, so I know how much I should be putting away.

The extra costs involved would likely all show up in rough lumber and the framing to lock up. Getting a house to lock up is likely the cheapest part of building a house . I would just plug the numbers into a standard calculator and then just add about 10% for the extra for the split level. I think that would give a fair rough estimate.

So, if it's a tri-level, should I calculate it as if it's a 3-story?

Also, part of the foundation is (or at least, could be) slab on grade while the other part would be dug out. Not sure how to calculate for that. The calculators usually make you pick one or the other.

So there isn't much difference, you could deal with it as 2 separate houses, one basement and one without or one slab on grade and one with crawl space.
The wall between them is a load bearing wall with a little more work than normal
so just subtract the price of siding for the mating walls.
Where I am the whole area would be dug out to the depth of the frost level or more.
The crawl space would be back filled to above the footing, compacted and 2" of concrete over poly.
The slab on grade would be back filled to with in 4" of the foundation and the floor would be over poly.
The crawl space would be at least 48" from concrete to bottom of joists. I think with a split level they usually do a sealed crawlspace with insulation on the inside of the foundation and consider the space as inside the envelope and conditioned space.

Hah, so in other words it's way more complicated to calculate!

I have friends that have split levels and tri levels and my opinion is I don’t find them very user friendly at all and then I see all that wasted basement space in the crawl area and I wonder why would someone pay extra for these designs.


But on the other hand I’m as practical as they come when it comes to design after spending a lifetime in designing machinery where style points don’t buy you much. Her brother just bought a very high end home and the first thing I did was count the facets on all the roofs and I came up with 22 when 4 could have got the house covered with two valleys instead of a dozen. There is something to be said for house design as nothing looks good that’s just a box.


I know this is off topic so sorry about that.

What I like about split-levels is you can isolate different types of living areas, and also when you do the open loft areas you can create really cool possibilities with the space. Like in my "dream home" I have a kitchen that looks out onto the den/living room half a floor below, but also a master suite that looks out over both of those levels, all three under one big ceiling, and all three sharing natural light from one big window wall and several skylights.

Another reason for the tri-level design is that I want to build into the side of a hill, so that you enter on the level of the kitchen/dining area but then can look downwards out the back windows at a beautiful pine-covered mountain vista below.