Construction Cost per Sq Ft Calculator
Construction cost from built up area and a rate a square foot, with the finish level, contingency and approval fees separated. Roughly half of a house is structure and half is finishing, and it is the finishing half that varies by a factor of three between basic and luxury.
Also called: house construction cost, cost per square foot calculator.
$3,726,000.00 for 1,800 square feet at $1,800.00 a foot after the standard finish adjustment. About 1684800 is structure and 1555200 is finishing, across 2 floors. The structure is predictable; the finishing half is what differs by around three times between a basic and a luxury specification, which is why two quotes at very different rates are often for very different houses. Contingency of 324000 and fees of 162000 sit on top of the 3240000 build, not inside it. Ten percent contingency is the working minimum, because no site survives contact with the ground plan intact. Spread over 14 months the outflow averages 266142.86 a month. Rates vary by city, season and contractor. Treat the figure as a budget with a stated contingency, not a quotation.
Where the money goes
Hover or drag for valuesCost by stage
| Stage | Share | Amount |
|---|---|---|
| Foundation and plinth | 14% | $453,600 |
| Structure and slabs | 28% | $907,200 |
| Masonry and plaster | 10% | $324,000 |
| Electrical and plumbing | 12% | $388,800 |
| Flooring and tiling | 13% | $421,200 |
| Doors, windows and joinery | 11% | $356,400 |
| Painting and finishing | 12% | $388,800 |
How this is calculated
A rate per square foot is the way the trade quotes and it hides an important split: the structure, foundation, frame, slab and walls, is fairly predictable, while finishing, flooring, fittings, joinery and paint, is where the range lives. A basic finish and a luxury one differ by around three times on the same structure. Contingency is not padding, it is the acknowledgement that no site survives contact with the ground plan intact, and ten percent is the minimum any builder would recommend. Approvals, plan sanctions and statutory fees are added separately because they scale differently and are often left out of a per-foot quote entirely.
area times rate, adjusted for finish level, with contingency and statutory fees added on top rather than absorbed- A
- Built up area
- r
- Base rate
- m
- Finish multiplier
Method and limits
What it assumes
- A rate covering material and labour, as trade quotes usually do.
What it deliberately does not model
- Site conditions, soil, access and slope can move the structural cost substantially before anything is built.
- Rates move with steel and cement prices, which are volatile enough to change a budget mid-project.
Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator
Frequently asked questions
- Why is the range of quotes so wide?
- Because the finishing half of the cost varies by around three times between basic and luxury specification. Two quotes at very different rates are often for very different houses.
- How much contingency is enough?
- Ten percent is the working minimum and fifteen is safer on an older site or a difficult plot. It covers what the ground and the drawings did not tell you in advance.