Price Per Square Foot Calculator
Derive price per square foot, weigh it against comparables, and see how much the choice between a simple and a size-weighted average moves the indicated value.
Price Per Square Foot Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Assumes value scales linearly with area, which it does not.
- Ignores land, condition, aspect, floor level and parking entirely.
- Three comparables only; a full analysis would adjust each for differences.
In short: Price per square foot is price divided by area — 229.73 on a 425,000 home of 1,850 sq ft. But a simple mean of comparables gives 228.13 psf and a size-weighted mean 227.97, a 292.28 swing in indicated value.
Formula
price per sq ft = price ÷ area
weighted mean = Σ prices ÷ Σ areas
[('subject psf', 'the ratio for the property in question'), ('simple mean', 'average of the comparable ratios'), ('weighted mean', 'total price over total area'), ('indicated value', 'comparable rate × subject area')]
Worked Example
- Divide price by area for the subject.
- Compute the same ratio for each comparable.
- Average them simply, and again weighted by area.
- Apply both to the subject area and note the spread.
- Explain any gap through condition, land or measurement basis.
A 425,000 home of 1,850 sq ft is 229.73 per foot. Three comparables give 231.40, 224.75 and 228.25 — a simple mean of 228.13 and a size-weighted mean of 227.97. Applied to the subject those indicate 422,045.23 and 421,752.95, a spread of 292.28 from the averaging choice alone. Note also that the smallest comparable shows a 2.96% higher rate than the largest, the usual non-linearity. Measured on 1,680 sq ft of net internal area the subject reads 252.98, a 10.12% difference for no physical reason.
Strengths & Limits Of This Model
Where this engine is strong
- Shows simple and weighted means side by side with the spread
- Quantifies measurement-standard risk explicitly
- Excludes rather than zero-fills incomplete comparables
Where it stops
- A screening tool, not a valuation
- No adjustment grid
Practical Use Cases
Sanity-checking an asking price
Comparing the subject rate against recent sales.
Screening listings
Spotting outliers quickly before deeper analysis.
Preparing an offer
Supporting a number with a defensible comparable rate.
Reviewing an appraisal
Testing which averaging method was used and what it moved.
Comparing across sources
Checking whether two rates were measured on the same basis.
Methodology & Editorial Standards
The subject ratio is price over area. Comparables are averaged two ways — a simple mean of the individual ratios and a size-weighted mean computed as total price over total area — and both are applied to the subject area so the valuation consequence of the choice is visible rather than buried. Comparables with a zero price or area are excluded rather than treated as zero. The net internal comparison exists to quantify measurement-standard risk, which is the largest single source of error in the method.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Price Per Square Foot Calculator — 10 Expert FAQs
10 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How do you calculate price per square foot?
Divide the price by the floor area. The arithmetic is trivial; the difficulty is entirely in which area you use, since gross external, gross internal and net internal measurements can differ by ten per cent or more on the same property and move the ratio by the same amount.
Is a lower price per square foot always better?
No. It frequently reflects a larger property, an inferior location, poorer condition, or simply a different measurement standard. The ratio is a screening tool for identifying outliers worth investigating, not a ranking of value.
Why do smaller homes cost more per square foot?
Because kitchens and bathrooms are the most expensive rooms per foot to build and every home needs them, so their cost is spread over fewer feet in a small property. Land, which does not scale with floor area at all, works the same way. Value is not linear in area, and this ratio pretends it is.
Should I use a simple or weighted average of comparables?
The size-weighted mean — total price over total area — is usually more defensible when comparables differ materially in size, because it stops a small unusual property from carrying the same influence as a large typical one. This page shows both and quantifies the gap, because the choice is rarely disclosed and often material.
Does price per square foot include land?
Not as a separate component, which is one of its central weaknesses. In markets where land is most of the value, two houses of identical floor area on very different plots will show similar rates while being worth quite different amounts.
What measurement standard should I use?
Whichever your market uses consistently, and then never mix sources. Residential listings frequently quote gross internal area while professional valuations may use net internal; comparing one against the other introduces a systematic error of around ten per cent that looks exactly like a pricing difference.
Do garages and basements count?
Usually not in the primary figure, or only at a discounted rate, and practice varies by market. Unheated space, conversions and outbuildings are treated inconsistently between sources, which is another reason comparables should come from one basis rather than several.
How many comparables do I need?
Three genuinely similar recent sales in the same submarket are worth more than ten loose ones. Similarity in size matters particularly here, because the non-linearity between size and rate means a comparable of very different area contributes a systematically biased figure however close it is geographically.
Can I use this for commercial property?
For a rough screen only. Commercial value is driven by income, so capitalisation of net operating income is the primary method, and the rentable-versus-usable distinction adds a further measurement complication on top of the ones described here.
Why does my figure differ from the listing site's?
Almost always measurement. Listing portals take area from whichever source is available — agent particulars, tax records, an old floor plan — and those disagree routinely. Before concluding a property is mispriced, confirm that both figures were computed on the same measured area.