SettingsSettings for this calculationUS
Measured inside the external walls, all storeys.
Gross internal area is the convention build rates are quoted against. Measure to the inside face of the external wall and include internal walls, stairs and circulation — excluding them understates the area and therefore the cost.
Your rate for the building itself, always per m².
Substructure up to finishes and services, excluding everything outside the footprint. Get this from a quantity surveyor, a builder's quote, or a comparable completed project — and be sceptical of any single national figure. This field wants the PER SQUARE METRE figure even when the rest of the page has switched to imperial. The rate carries no dimension, so the unit toggle leaves it exactly as typed — while the floor area above does convert, and so does the breakdown line reporting the all-in cost per unit of GIA. A US price book or cost guide quotes the same money as a per-square-foot rate, and 1 m² is 10.7639 of those units: 2,200 per m² is 204.39 in them. Nothing stops you entering 204.39 — it is inside the 0 to 100,000 this field accepts, so it is neither clamped nor queried, just taken — and it prices the building at 9.29% of its cost. With every other field left at its default, a 150 m² house drops from 406,560 to 37,771, which still reads like a budget. Multiply a per-square-foot rate by 10.7639 before entering it.
Drives, drainage, landscaping, boundaries.
The most consistently underestimated line in self-build. Site clearance, a drive, drainage runs to the sewer, retaining where the ground slopes, boundary treatment and planting are all outside the building rate and together commonly reach 10-15% of the build.
Water, electricity, gas, telecoms, sewer.
Quoted individually by each utility and non-negotiable. A long run to a rural plot, or a road crossing, can multiply this several times over — get the quotes before you buy the plot, not after.
Architect, engineer, surveyor, building control.
Eight to fourteen percent of construction is typical for a full service. Structural engineering, energy assessment, warranty inspection and building control fees sit inside this.
Ten to fifteen percent on new build.
Higher on a difficult or unknown site. Ground conditions are the classic overrun: a foundation design that changes after the trial holes can add a substantial sum before anything is built above ground.
Whatever applies where you are.
Rates and reliefs vary sharply by jurisdiction and by whether the work is new build, conversion or renovation. Several countries treat new dwellings differently from alterations — check your own position rather than assuming.
Total project cost
Needs your Build rate (per m² GIA)
This page does not assume a price. Enter yours and the answer appears here.
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Cost to Build a House Calculator — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- 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
Inputs used
- Gross internal floor area
- 1610 sq ft
- Build rate (per m² GIA)
- External works
- 0
- Service connections
- 0
- Design and professional fees (%)
- 10
- Contingency (%)
- 12
- Sales tax / VAT (%)
- 0
What this calculation does not cover
- Excludes the land, its acquisition costs and any transfer tax on it.
- Excludes finance costs, which on a self-build drawn down over eighteen months are a substantial and separately-modelled figure.
- Excludes planning obligations and infrastructure levies, which in some jurisdictions are charged per square metre and are payable before work starts.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-05 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations2
- 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
Cite this page
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