Building Costs per Square Foot

As a home gets larger, I was wondering how to estimate construction cost beyond a standard square foot estimate.

For example, I plugged in numbers on the free cost estimating software for a 3,000 square foot home of average quality in Southern California and I came up with a cost of about $100/square foot, $300,000.

If I double the size of the house to 6,000 square feet, the calculator comes up with $600,000, still $100/square foot.

How can that be? I can't believe there are $300,000 in additional material and labor costs.

For example, it can't cost twice as much to build a 20 foot x 20 foot bedroom versus a 10 foot x 10 foot bedroom. It's just more lumber and drywall.

Any words of wisdom would be appreciated.


Hi David,

I always love the” It's just more lumber and drywall”. That’s what professional home builder’s hear all the time when a client gets an estimate or bid.
Actually, it’s more lumber, drywall, insulation, floor covering, HVAC capacity, roof shingles, foundation, siding, labor, insurance, more bathrooms, etc., etc.

Using the same “Average Quality Class” for design and materials on the construction estimating software for both a 3000 sq ft and 6,000 sq ft version of a typical one story ranch on slab home (no land, impact fees, or other local fees, and no garage) in San Bernardino CA, I came up with an approximate total cost to build for 2016 of $262.511 for the 3,000 sq ft version and $504,417 for the 6,000 sq ft version.

Homes are measured in square feet of living area (heated space).
More square footage equals more money. That's pretty simple.
How much more? That’s the hard part.

That’s why a cost estimate based on “cost to build per square foot” is at the very best, a very rough estimate.

That’s why the Estimating Software has 6 different “Quality Classes” for 10 major categories.

But as I always say, until you get actual bids and estimates from contractors and suppliers, or General Contractor’s if you are using one, your best efforts at estimating will remain “approximate” estimates.

For more thoughts on this simple yet complicated thought, read my answer to the frequently asked question “Is the cost per square foot to build the same for any size house?” on my FAQ’s.(Scroll down)

Well David, you can see that your question is a frequently asked question.

Good luck, Carl Heldmann

How Much Does It Cost To Build a House in Massachusetts

Good afternoon Carl, I have to admit, I love the posts you have up here as
they are very informative to me.

My wife and I have selected a house plan to build from Don Gardner plans.

The plan is The Manchester - House Plan# W-718.

Would you be able to use this as one of your examples?


Hi Michael,

Sure, I’d be glad to.

You chose an attractive “Traditional” house plan from Donald A. Gardner Architects, Inc.

They define a traditional home plan as a home that “typically features multiple gables, hipped roofs and covered entryways with a clapboard or brick facade creating a grand appearance.”

Their traditional house plans (Don Gardner plans) feature open floor plans in various sizes from 1600 - 5000 square feet.”

The Manchester is a 3 bedroom 2.5 bath Traditional home that has 2,261 Sq. Ft. of total living area and a Bonus room of 235 Sq. Ft.

I ran a cost to build estimate for this home plan for Pittsfield, MA 01201 with brick veneer and an unfinished basement and came up with a total cost to build of, $360,475 (including a General Contractor’s markup of $44,397) or $ 159 per sq ft of heated living area.

Without the brick veneer (using Hardboard or inexpensive stucco siding) I came up with a total cost to build of $326,535 (including a General Contractor’s markup of $40,010), or $144 per sq ft of heated space.

Except for the brick veneer (Quality Class # 2) and the unfinished basement (quality Class # 5 or better), I used the quality class # 6 throughout (Minimum Standard Quality) for all the other categories,

Single-family homes vary widely in quality and the quality of construction is a major cost variable.

This estimate is a "rough" approximate estimate for 2016.

Land, land development costs, impact fees, if any, and any other local fees, are NOT included in any of the estimated costs to build that I provide.

Well Michael, by using the cost to build calculator found on my Getting Started page you can perform your own cost analysis, varying the quality of construction to fit your budget.

Have fun,
Carl Heldmann