A number that looks objective and is not
Price per square metre feels like the one honest figure in property. It appears to strip out size and let you compare like with like across streets, cities and countries. In fact it is a fraction, and both halves are defined differently in different places, by different parties, sometimes within a single transaction. The same apartment at the same price can honestly be described with per-square-metre figures that differ by a quarter or more. The figure is still useful. It just has to be read as the output of a definition rather than as a measurement.
The denominator: which area?
The main variants you will meet are:
- Net internal or usable area. The floor you can walk on inside the unit, measured to the inner face of walls. Internal partitions may be included or excluded.
- Gross internal area. Measured to the inside face of external walls, including internal partitions.
- Gross area including a share of common parts. Your unit plus an allocated proportion of stairs, lobbies, corridors and plant rooms. This inflates the area and deflates the figure.
- Weighted outdoor space. Balconies, terraces and loggias are frequently added at a coefficient, meaning a fraction of their true area, and the coefficient varies by convention.
- Ancillary areas. Basements, cellars, garages, attics and covered parking may be inside or outside the figure, sometimes at their own weighting.
There is a further source of divergence: who measured. The cadastre record, the developer’s brochure, the agent’s listing and a surveyor’s report can all state a different area for the same unit, and the registry figure is often the one that governs legally.
The numerator: which price?
- Asking, agreed or registered transaction price. Asking prices are aspirations and can sit well away from what is achieved.
- With or without transaction taxes and fees. A figure on total acquisition cost is a different statistic from one on the headline price.
- With or without bundled extras such as parking, storage, furniture packs and appliances.
- With or without incentives. Developer contributions, free service charge periods and paid fees reduce the effective price without changing the advertised one.
Worked example
These numbers are invented to show how definitions move the result. They describe no real property.
Suppose a flat has 78 square metres of net internal area, a 10 square metre balcony, and an allocated 9 square metre share of common parts. The price is 260,000 in local currency, with a parking space offered separately at 20,000.
- On net internal area: 260,000 / 78 = 3,333 per square metre.
- On net internal plus the balcony at a 50 percent coefficient, so 78 + 5 = 83: 260,000 / 83 = 3,133 per square metre.
- On gross area including the full balcony and the common parts share, so 78 + 10 + 9 = 97: 260,000 / 97 = 2,680 per square metre.
The range runs from 2,680 to 3,333, so the highest figure is about 24 percent above the lowest with no change to the property or the price. Now bundle the parking: 280,000 / 97 = 2,887 per square metre, which reads as more expensive than the previous line but is the same flat plus a parking space.
Compare a listing quoted on the first basis against a market average computed on the third, and you will conclude the flat is expensive when it may not be. This is the most common error in cross-border property comparison.
| Component | Variants you will meet | Effect on the figure | How to normalise |
|---|---|---|---|
| Area basis | Net internal, gross internal, gross including common parts | Larger area lowers the price per square metre | Ask for the net internal figure and rebuild from there |
| Balconies and terraces | Excluded, included fully, or weighted | Can move the figure by several percent | Ask for the coefficient used, and the raw outdoor area |
| Parking and storage | Bundled or priced separately | Raises price without raising measured area | Strip them out of the price, or add their area |
| Price type | Asking, agreed, registered | Asking prices usually sit above achieved prices | Use registry or notarial data where published |
| Taxes and fees | Inside or outside | Can add a meaningful percentage | Compare on headline price, then separately on total cost |
| Average type | Mean or median | A few high-value sales pull a mean upwards | Prefer medians for skewed markets, and check the sample size |
Questions that make a figure usable
- What area definition was used, and was it taken from the registry, a survey or a brochure?
- Are balconies included, and at what weighting?
- Is the price asking or achieved, and over what period?
- Does the price include parking, storage, furniture or any incentive?
- Does it include or exclude transaction taxes?
- What geography does the figure cover, and does that boundary match the one you have in mind?
- Is it a mean or a median, and how many observations sit behind it?
- What currency and what date, since a cross-currency comparison also embeds an exchange rate?
What the figure cannot tell you
Even correctly normalised, price per square metre discards most of what determines value: floor level, aspect and light, layout efficiency, ceiling height, condition, energy performance, noise, lift access, outdoor space quality, and the state of the building’s reserve fund. Two units at an identical figure in the same building can be quite different propositions. We treat it as a screening tool for narrowing a search, then stop using it once the shortlist is short.
Where the underlying data comes from matters as much as the definition. Land registries, notarial bodies and statistics offices publish transaction-based figures in some countries. Portals publish listing-based figures, which measure supply rather than sales. We would always note which of the two a headline number is, because they answer different questions.
Measurement conventions, publication practices and the availability of transaction data differ by country, and different bodies within one country apply different standards. For any specific property the area that matters legally is the one on the registered title, and a qualified local surveyor, lawyer or notary should confirm it before you rely on any comparison.
How to Use This Guide
Every worked example on this page is illustrative. The figures are chosen to show how the calculation behaves, not to report current market rates. Costs, tax rules and eligibility criteria differ by country and change over time, so take the method from this page and put your own current figures into it. Browse the rest of our guides, or see how we source and check our comparison figures on the about page.
Information only. This article explains how costs and rules are structured. It is not financial, tax, legal or immigration advice, and it is not a recommendation to buy any property, vehicle or investment. Confirm anything that affects a decision with the relevant local authority or a qualified professional before you act on it.
Last updated: August 14, 2026