Construction Cost Calculator
Estimate the cost of a new build, addition or gut renovation by the square foot.
Project Specifications
Structural Extras & Upgrades
Construction budgets are built up from a cost per square foot, then adjusted for how the house is finished, how tall it is, and where it's being built. This calculator walks through those factors — floor area, finish quality, project type, number of stories, and regional cost index — to produce an estimated total and a likely price range, then breaks that total across the major stages of a build. It's a planning tool for early conversations, and it runs entirely in your browser.
How the estimate is built
The core of the estimate is a base rate per square foot that reflects the finish level — economy builder-grade at the low end, rising through standard and luxury to a high-end custom rate — multiplied by your floor area. Several adjustments then apply on top:
Estimate = Area × Base rate × Project factor × Story factor × Regional index (+ extras)
A ground-up build uses the base figure, an addition costs more per foot because it has to tie into an existing structure, and a gut renovation costs less than new construction since the shell already exists. Two- and three-story homes carry a small complexity premium, and a regional index scales the whole figure up or down for the higher or lower construction costs in different parts of the country. Optional extras like a finished basement, a larger garage, a deck, or premium landscaping are added as lump sums.
The range and the component breakdown
Rather than a single false-precision number, the tool shows a range from about ten percent below to fifteen percent above the estimate, reflecting how real bids come in. It also splits the total across the stages of a build — foundation, framing, exterior, mechanical systems, drywall, interior finishes, kitchen and bath, and permits — using typical percentage shares, so you can see roughly where the money goes. Every figure here is a national-average planning estimate, not a quote. Actual costs swing with local labour markets, material prices, site conditions, and your specific design choices, so use this to frame a budget and then get real bids from local contractors.
Frequently Asked Questions
How accurate is this estimate?
It is a planning-level estimate based on average cost-per-square-foot figures and typical adjustments, which is why it shows a range rather than one number. Real bids depend on your local market, site, and design, so treat it as a starting point, not a quote.
What does the regional index do?
It scales the estimate for where you are building. Construction costs run well above the national average in some states and below it in others, so the index multiplies the base figure up or down to reflect local labour and material prices.
Why is a remodel cheaper per square foot than a new build?
Because a gut renovation reuses the existing foundation, framing, and exterior shell. The calculator applies a lower factor for remodels and a higher one for additions, which must integrate with the current structure.
What is the component breakdown for?
It divides the total across the major stages of construction — foundation, framing, systems, finishes, and so on — using typical percentage shares, giving you a rough sense of where the budget goes rather than exact line-item costs.
Is anything I enter saved?
No. The calculation runs entirely in your browser and nothing you enter is uploaded or stored.