Should a balcony or terrace be counted in the area?

Not in the certified living area under most standards, because they are not enclosed heated space. They still carry real value, which is why many markets quote them separately or weight them at a fraction of indoor area. Keep them out of the divisor and price them as a separate line, rather than quietly folding them in and inflating the area.

How wrong can a stated area be before it matters legally?

In France, if the certified private area of a flat in a co-ownership turns out to be more than 5 percent smaller than stated in the deed, the buyer can claim a proportional reduction of the price, with a one-year limit from the deed. On the numbers in this article, a shortfall of that kind on a $429,000 purchase is worth thousands, so it pays to check the certificate rather than the listing.

Why is the neighbourhood average always different from my listing?

Because an average blends unit sizes, floors, conditions and dates of sale that your specific listing does not share. Averages are useful for direction and for spotting an outlier, not for setting an offer. A short list of genuinely comparable completed sales — same segment, same street or block, last six months — beats any published average, however large the sample.

How to Compare Price Per Square Foot Without Comparing Two Different Things

Published 7/7/2026 · 6 min read · Real-estate calculators

Camille Laurent — Finance writer at OneKitly

Tax · Personal finance

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In short

Divide the price by the living area, then check that the two areas you are about to compare were measured under the same rule — that second step is where the answer actually comes from. Take two listings: one at $429,000 for 1,780 square feet is $241 per square foot; one at $465,000 for 2,050 square feet is $227, which looks 5.9 percent cheaper. But if that 2,050 includes a 400 square foot finished basement, its above-grade living area is 1,650 square feet, the price per square foot is $282, and the supposedly cheaper home is 16.9 percent more expensive than the first. Nothing about either property changed; only the measuring convention did. Price per square foot is a screening tool that tells you which listings deserve a viewing, never a valuation — it says nothing about the floor, the light, the condition, the energy rating or the outdoor space.

A laser level projecting lines across an empty room. — Tima Miroshnichenko · Pexels · Pexels

The division takes a second; the trap is the area. A listing that looks 6 percent cheaper per square foot turns out to be 17 percent more expensive once both are measured the same way.

Area is a legal definition, not a measurement

Two surveyors with the same laser will report different areas for the same home, because what counts is decided by a rule rather than by the tape. In France the Carre rule excludes any space under 1.80 metres of ceiling height, along with walls, partitions, stairwells and openings; a converted attic can therefore be entirely real, entirely usable and entirely absent from the certified figure. Other markets draw the line elsewhere: some count balconies at a fraction, some exclude below-grade space from living area however finished it is, and gross floor area includes the thickness of the walls that net internal area does not.

So a price per unit of area is only meaningful next to the name of the standard it used. Written without that name it is a number that cannot be checked, and comparing two of them is comparing two definitions rather than two homes. When a listing does not say, the honest move is to ask for the certificate or measure the rooms yourself and rebuild the figure.

The worked comparison, both ways round

The first listing is $429,000 for 1,780 square feet, which is $241 per square foot. The second is $465,000 for 2,050 square feet, or $227 — a 5.9 percent discount, and on a screening spreadsheet it wins. Then the detail: 400 of those square feet are a finished basement, which the local market treats as below-grade and does not put in living area. Above grade the home is 1,650 square feet, the ratio becomes $282, and the discount is a 16.9 percent premium.

Neither figure is a lie; they answer different questions. The larger area answers what you can walk through, the certified area answers what the law says you bought. Both belong in the decision — but only one of them can sit in a comparison, and it has to be the same one on both sides.

What the ratio is good for, and where it stops

Used as a filter it is excellent: it sorts thirty listings into the five worth a Saturday, and it makes an outlier visible in a second. Used as a valuation it fails, because it treats every square foot as interchangeable when a ground-floor room facing a courtyard and a top-floor room facing south plainly are not. Small homes also carry a structurally higher price per unit of area than large ones in the same building, since the kitchen and bathroom cost roughly the same whatever the total area.

One conversion is worth keeping in mind if you read listings across both systems: one square metre is 10.764 square feet, so a price per square metre becomes a price per square foot by dividing by 10.764, and the other way round by multiplying. The unit changes, the measurement problem does not — an area standard from one country converted into the other country's unit is still that first country's standard.

Worked with our own calculator

Price per square meter calculator

Given

Total price: $600,000.00
Area (m²): 83
Value of parking, garage or land to exclude: $5.00

Result

Price per m²: $7,228.92
Price per ft²: $671.59
Price per m² of living space alone: $7,228.86

These figures are produced by the calculator below, not typed in by hand — they are recomputed whenever the tool changes.

Run it on your own figures →

Frequently asked questions

Should a balcony or terrace be counted in the area?: Not in the certified living area under most standards, because they are not enclosed heated space. They still carry real value, which is why many markets quote them separately or weight them at a fraction of indoor area. Keep them out of the divisor and price them as a separate line, rather than quietly folding them in and inflating the area.
How wrong can a stated area be before it matters legally?: In France, if the certified private area of a flat in a co-ownership turns out to be more than 5 percent smaller than stated in the deed, the buyer can claim a proportional reduction of the price, with a one-year limit from the deed. On the numbers in this article, a shortfall of that kind on a $429,000 purchase is worth thousands, so it pays to check the certificate rather than the listing.
Why is the neighbourhood average always different from my listing?: Because an average blends unit sizes, floors, conditions and dates of sale that your specific listing does not share. Averages are useful for direction and for spotting an outlier, not for setting an offer. A short list of genuinely comparable completed sales — same segment, same street or block, last six months — beats any published average, however large the sample.

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