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Cost to Build a House Calculator

Assemble a whole-build budget: shell, externals, professional fees, prelims, contingency and tax — in the order they compound.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-27 · v1.0.0

Market
Imperial · sales tax

Total project cost

0 currency

Check your inputs

This calculator contains no market rates. Every rate is yours to supply, because a published national average is wrong for almost every individual project and budgeting against one is how projects run out of money.

Building
0 currency
External works
0 currency
Service connections
0 currency
Contingency
0 currency
Professional fees
0 currency
Tax
0 currency
All-in cost per m² GIA
0 currency/m²
Uplift over the bare build rate
0 %

Running these inputs gives 0 currency as the total project cost. Note that gross internal floor area and build rate (per m² gia) sit at the edge of the range this calculator was checked against, so treat the output as indicative rather than settled. Expect some drift against the real job; the calculation is solid but conditions on site are not. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Element-based build-up. Rates are user-supplied; no market data is embedded.
  • Order of application matters: contingency on construction, fees on the contingent sum, tax on everything

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why does the order of the percentages matter?
Because each one is applied to the running total, not to the original figure. Contingency goes on construction; fees are charged on the contingent sum, because the professional team is managing that work too; tax applies to everything. Adding 12% and 10% as though they were both on the base understates the total — the breakdown's uplift figure shows how far the finished number sits above the bare build rate.
What gets forgotten most often?
External works and service connections, in that order. The build rate covers the building, and people reasonably but wrongly assume it covers getting to the building. A drive, drainage to the sewer, retaining walls on a sloping plot and boundary treatment routinely reach 10-15% of the build cost on their own, and utility connections to a rural plot can be many times what an urban one costs.
Why does this not include the land?
Because land is a separate transaction with its own tax, its own finance and its own timing — and because mixing it in makes the cost per square metre meaningless for comparison. Price the plot, its transfer tax and any planning obligations separately, then add this figure to them.