Frequently asked questions
Common questions about Mi Parcelita, Spanish cadastral references and the plot calculations.
What is Mi Parcelita?
A web app for studying what fits on a plot of land in Spain. Open the plot by its cadastral reference, place houses, pools, garages, courts or trees on the real map and terrain, and see the coverage, floor-area ratio, setbacks and sunlight straight away.
How do I view a plot by its cadastral reference?
Type the cadastral reference into the search field on the home page, for example 3294035QA5239S. Mi Parcelita downloads the plot's official outline, and the existing buildings if you tick the box, from the Catastro's INSPIRE service, and opens it in 3D on the PNOA aerial photo and IGN terrain.
Where do I find the cadastral reference?
On the IBI property-tax bill, the deeds or a land-registry extract (nota simple), or by searching by address or on the map at the Catastro's website (sedecatastro.gob.es). A plot's reference has 14 characters; a property's has 20, the first 14 being the plot's. Mi Parcelita accepts both.
How is the floor-area ratio calculated?
It adds up the built floor area: footprint times floors for every roofed building you place (carports and pergolas count 50%), plus the official floor area of existing buildings. The floor-area ratio is that total divided by the plot area, in m² per m².
How is coverage calculated?
It is the share of the plot covered by the footprint of roofed buildings, new and existing. Paths, terraces, lawns and pools don't count towards coverage, though paved ones count as impermeable surface.
Does it check my town's planning rules?
Not automatically. You enter your plan's limits (maximum floor-area ratio, maximum coverage, height and number of floors) and the setback, and Mi Parcelita shows whether the plan meets them. Always check the current planning rules with the town hall.
What is a setback and how is it drawn?
The minimum distance between buildings and the plot boundaries. In Mi Parcelita you enter the metres and a dashed line is drawn inside the plot. Roofed buildings, and optionally pools, that cross it turn red.
Where should the pool go to get the sun?
Turn on the sun-hours map. It computes the hours of direct sun on every part of the plot for the day you choose, with the shadows of your buildings, trees, neighbouring buildings from the Catastro and the terrain, distant mountains included. Pick a summer day and move the pool to the sunniest area.
Can I design the house in 3D?
Yes, as massing: a modern or traditional one- or two-storey house, villa, cabin or apartments, with a flat, gable, hip, mono-pitch or A-frame roof and editable sizes. It is meant for studying fit, orientation and shadows, not as a detailed architectural model.
What does the AI assistant do?
Describe what you want, for example "a house, a garage and a pool making the most of the sun", and it proposes a layout that respects the setback, distances and limits you have set. It checks overlaps and clearances, explains each change and lets you accept or discard it.
Is it free? Do I need to install anything?
Opening plots, placing elements, measuring, calculating and studying the sun are free and run in the browser, on phones too, with nothing to install. The plan is saved in your browser and you can download it as a project file.
Does it work outside Spain?
The cadastral search, the aerial photo and the terrain use Spanish services. You can open a GML file from elsewhere on OpenStreetMap, but the ground will be treated as flat.
Is the data official?
It comes from official public services (Catastro and IGN), but Mi Parcelita is a tool for early studies: its figures are indicative and do not replace a technical project, municipal rules or land-registry information.