The Spanish cadastral reference: reading the 20 characters

Sooner or later it turns up without explanation: in an estate agent's listing, a draft contract, a tax bill. A string such as 9719601DD6891H0003HU. This is the cadastral reference (referencia catastral), the number under which Spain's property cadastre (Catastro Inmobiliario) records each property. Once you can read it, you can check the officially recorded basics of a property yourself, and compare them with what the seller says.

How is the cadastral reference built?

In three parts, plus a short form. The full reference of one unit, for example a flat, has 20 characters made of digits and capital letters.

The first 14 characters identify the plot (parcela). For urban land, the first seven describe the block and the next seven the plot within it, together with the map sheet on which it is drawn. Rural land is coded differently, with province, municipality, sector and plot number.

Characters 15 to 18 identify the unit on that plot. A block of flats therefore has one plot number but a separate unit number for each flat, garage space or storeroom. In the example, 0003 is the third unit recorded in the building.

• Characters 1 to 7: Block. For rural plots, this part holds the province, municipality and sector instead.
• Characters 8 to 14: Plot. The plot within the block, plus the map sheet. Characters 1 to 14 together identify the plot.
• Characters 15 to 18: Unit. Flat, garage or storeroom on this plot. 0003 is the third unit recorded.
• Characters 19 to 20: Check characters. Calculated from the 18 characters before them. A typo therefore returns no result rather than the wrong one.

Then the check characters. They are calculated from the preceding 18 and catch typing errors, so a reference copied wrongly usually returns no result rather than the wrong property.

You will also meet a short form of 14 characters. It names the whole plot and says nothing about the units on it.

Where will you find the reference?

On any document that deals with rights over the property. Spanish cadastral law requires the reference in public deeds (escrituras), in court decisions and in documents about rights in rem, and, where the law provides for it, in the land registry (Art. 38 TRLCI). Every piece of information issued by the land registry must give it too (Art. 10 Ley Hipotecaria). In practice that means your nota simple, the land registry extract, carries the number.

A listing may show it or may not. If yours does not, ask the agent for it before anything else.

Spain's official province codes are worth knowing for search forms: 07 stands for the Balearic Islands, 03 for Alicante, 29 for Málaga.

What can you look up free of charge?

Looking up cadastral data through the Catastro's open services costs nothing. The reference is all you need.

By law, a cadastral description covers the location, the cadastral reference, the area, the use, a graphic representation on the cadastral map, the cadastral value and the cadastral holder (Art. 3 TRLCI). For the example property in Palma, the cadastre records a unit of 137 m² on a plot of 194 m².

Who owns the property, and what is charged on it?

The land registry answers that. Its purpose, in Article 1 of the Ley Hipotecaria, is to record acts and contracts on ownership and other rights in rem over real property. Rights entered there are presumed by law to exist and to belong to the registered holder (Art. 38 Ley Hipotecaria).

The cadastre is an administrative register of the Ministry of Finance that describes property, and it serves fair taxation and the fair distribution of public funds. The cadastral law leaves the land registry's competence and the legal effects of registration untouched. Cadastral data are presumed correct unless proven otherwise, but the land registry's legal statements prevail (Art. 2 and 3 TRLCI).

For ownership and other rights over the property, order a nota simple. The Colegio de Registradores describes it as purely informative.

Why does the listing give a different area?

Partly because the two figures can measure different things. The cadastral area is built area (superficie construida): the built surface of the private part plus a share of the common areas.

What counts in the cadastral area?

The Catastro's certification guide sets out three rules that move the figure:

• Covered balconies, terraces and verandas count at 50 per cent, and at 100 per cent when closed on three sides.
• Rooms under 1.50 metres high do not count for residential use.
• The share of common areas is only an approximate split made for cadastral valuation.

A listing may quote built area including the full terrace, or usable area (superficie útil). Ask the agent which one it is. Building work is another cause. The preamble of Ley 13/2015 names changes that one register learnt of and the other did not, together with the fact that registration in the land registry is voluntary, as reasons why the description in the cadastre and the description in the registry drift apart over the years.

How far apart can the figures be? In the court auctions we record, 97 items show both a portal area and the cadastral area of the linked property (as of 30 September 2026).

• Up to 5 per cent15items
• 5 to 20 per cent23items
• More than 20 per cent59items

The median gap is 31.7 per cent. In 30 cases the portal area is more than 5 per cent larger, in 52 more than 5 per cent smaller. The portal does not state consistently which kind of area it means, so a gap alone proves no error.

When does the land registry accept a difference?

The Ley Hipotecaria treats the graphic and the written description of a registered property (finca) as matching if they cover the same land and the area differs by no more than 10 per cent of the registered area (Art. 9). A difference of up to 10 per cent can be entered without a formal procedure if a matching cadastral certificate supports it, and a difference of no more than 5 per cent of the registered area can be corrected without one as well (Art. 201.3). These figures come from the consolidated text, last updated on 3 January 2025, with the articles as amended by Ley 13/2015 in force since 1 November 2015. What the registrar decides for your specific property is authoritative.

Flats are a special case. The correction procedure of Article 201 is excluded for buildings and units under horizontal division (división horizontal); there the original title has to be corrected. On the cadastral side, the cadastre can open its own procedure to resolve a discrepancy with reality (Art. 18 TRLCI).

How do you check the outline on the ground?

Lay the plot boundary from the cadastral map over a current aerial image.

If a pool, a wall or part of a building stands outside the boundary, that is a question for your lawyer, and not yet a defect. Look at the nota simple as well. It must say whether the finca is graphically coordinated with the cadastre as of a given date (Art. 10 Ley Hipotecaria). Only after coordination is the property presumed to have the location and boundaries of the cadastral graphic.

The aerial series of the Instituto Geográfico Nacional reach back to 1956, the year of the Vuelo Americano. An extension missing on the old image and present on a new one can be roughly dated that way.

A property check starts from the same reference and adds further official sources by the plot's location.

What should you do before talking price?

With the reference in hand, a short order of work:

• Get the reference. From the listing, the draft contract or the nota simple.
• Look it up in the cadastre. Area, use and outline, free of charge.
• Compare with the listing. Ask which area the agent quotes.
• Add the land registry. Ownership, charges and the coordination note are in the nota simple.

The same number also works for court auctions, where it links the portal entry to the official data; see Spanish court auctions. You can start a property report with it today.

Summary

The cadastral reference has 20 characters for a unit and 14 for the plot, with two check characters at the end. Deeds, court decisions and every nota simple must show it. The cadastral lookup is free and describes the property; ownership and charges sit in the land registry, whose statements prevail. A different area in the listing can reflect a different way of measuring, and the land registry's 10 per cent and 5 per cent thresholds apply only as the registrar decides in your case.