Look up any address in the BAG Viewer
Type an address, postcode or BAG number and see the building, dwelling unit and cadastral parcel on the map. With aerial imagery, neighbourhood data and measuring.
Free, no account needed. Data straight from the BAG, the Cadastral Map, CBS and RIVM.
Search a property and see what's on record
Type an address or parcel. You'll see the free BAG data straight away. The owner's name is paid, and we show you honestly where it's cheapest to get.
Open, public data via PDOK Locatieserver (BAG, Kadaster). Ownership data is subject to the Kadaster's terms of supply and the GDPR.
The power of BAG data within reach
Analyze buildings, use and historical data directly from one platform
What is the BAG?
The BAG (Basisregistratie Adressen en Gebouwen) is the official, public register of every address and building in the Netherlands. Municipalities are the source holders; the Kadaster runs the national facility and the official BAG viewer. The data is open: you can look up an address for free, without an account. Note that the BAG covers buildings and addresses, not parcels, boundaries or ownership, which sit in the cadastral register.
The BAG is the Basisregistratie Adressen en Gebouwen: the official register of every address and every building in the Netherlands. Municipalities are the source holders and record what stands on their territory; the Kadaster maintains the national facility where all those municipal administrations come together into one national dataset.
It is a base register, and that is more than a formality. Government bodies are required to use the BAG as the authoritative source for address and building data, and required to report errors they encounter. As a result the register corrects itself continuously, which is why you can build on it.
The data is open. You need no account, licence or subscription to look up an address, and there is no price tag. What is scarce is the ability to work with it in a structured way: searching on attributes instead of addresses, filtering across a whole municipality, and being alerted when something changes.
A common misconception is that the BAG is about land. It is not. The BAG is about buildings and addresses. Parcels, parcel boundaries and ownership sit in the cadastral register, a separate source with its own custodian.
Object types in the BAG
The BAG has seven object types. These four are the ones you meet in practice, and the difference between them explains most of the confusion.
Pand (building)
The physical structure: the outer shell. A terrace of ten houses can be one building, or ten. The construction year attaches to the building, not to the home inside it.
Verblijfsobject (dwelling unit)
The smallest independently usable unit with its own entrance: a home, an apartment, an office unit. This is what the usable floor area and the use attach to.
Nummeraanduiding (address)
The address itself: postcode, house number, letter and addition. One dwelling unit can carry several addresses, for example a shop with its own side entrance.
Standplaats & ligplaats
Official sites for a mobile home or houseboat. They do have an address, but no building, and often no registered floor area.
Every object carries its own sixteen-digit BAG ID, beginning with the four-digit municipality code. That ID does not change when a street is renamed or a building changes use, which makes it the most reliable way to track objects over time. The usable floor area and the use are found on the dwelling unit, not on the building. If a term here is unfamiliar, it is explained in the glossary.
The Kadaster's official BAG viewer, and where it stops
The Kadaster provides a free BAG viewer in which you can look up any Dutch address. You see the building on the map, with construction year, use, floor area, status and the matching identifiers. That is the register itself: if you need to consult an object officially, view its history or report an error, that is the place.
It simply stops at the BAG. There is no cadastral parcel, no aerial imagery, no neighbourhood or environmental data, and you look at one address at a time. That is not a shortcoming — it is exactly what a base register should do. But the question behind "what is here?" is rarely a BAG question alone.
So we built our own viewer, also free and without an account: the same BAG objects, but next to the cadastral parcel, with sixteen map layers about the surroundings and the option to draw an area. If your question goes further — every address inside an area or filter, exporting, or being alerted when something changes — that is where the paid part of Revelop begins.
Official BAG viewer (Kadaster)
- One address at a time, no cadastral parcel on the map
- BAG only — no neighbourhood, noise or nature layers
- No aerial imagery, no 3D
- Length measurement only
- The official register: this is where you report an error
Our BAG Viewer — also free
- Building and cadastral parcel side by side, with surface area
- Sixteen map layers: WOZ, population, amenities, noise, Natura2000
- Aerial, topographic or grey — and jump to your own location
- Draw an area and see the CBS figures inside it straight away
- Every BAG number links through to the official register
Who is the BAG Viewer for?
Choose your target audience and discover relevant benefits of the BAG Viewer.
Property Developers
- Find and analyze parcels and buildings in one overview
- View historical use and building status
- Combine BAG data with other datasets for deep insight
Investors
- Analyze building statuses and historical data
- Identify opportunities based on complete BAG information
- Real-time updates enable quick decisions
Already managing a portfolio rather than building one? See asset managers and property managers for what happens after acquisition.
Why BAG Viewer?
All BAG data in one place, directly accessible within a clear tool.
Extensive BAG data
All buildings in the Netherlands with historical information and usage data.
Advanced filters
Quickly filter by address, status, usage purpose and more to instantly find the right objects.
Lead Management & Analysis
Mark objects as leads, track historical data and combine with other datasets for optimal insight.
Ready to try the BAG Viewer?
Join hundreds of professionals already benefiting from direct access to BAG data.
Statuses: what the BAG tells you about a building's life cycle
Every object carries a status, and for real estate professionals that is often more interesting than the floor area. A building runs through a fixed sequence: permit granted, construction started, in use, possibly renovation, and finally demolition permit granted and demolished. A dwelling unit has its own sequence, from formed to in use to out of use.
Those statuses are signals. Buildings marked out of use in a district where prices are rising, new-build where construction has just started, or a demolition permit on a location you follow: it is all in the same register, and it changes daily. Combined with the permits filed on the same address, and with the parcel mutations Grondradar tracks, a status becomes a signal instead of a field value.
Frequently asked questions about the BAG
What is a BAG number?
Is the BAG free to consult?
What is the difference between a pand and a verblijfsobject?
How current is the BAG?
Something in the BAG is wrong. What now?
Does the BAG show who owns a building?
Sources
Official sources for this page. Last checked: August 2026.
BAG via PDOK
The Basisregistratie Adressen en Gebouwen is open data: address and building data can be consulted for free, without an account, through the open PDOK services.
Municipalities (source holders)
Municipalities are the source holders of the BAG and record what stands on their territory; public bodies must report errors, so the register corrects itself over time.
Kadaster (national facility)
The Kadaster runs the national facility where the municipal administrations come together into one dataset, and provides the official BAG viewer.
Looking for something specific?
Look up floor area
The registered usable floor area per address, and why it differs from what an estate agent measures.
Look up floor areaCadastral map
From building to land: parcel boundaries, parcel numbers and cadastral size.
To the cadastral mapFind the owner
Who owns this building? The free route, the paid route and what is allowed at scale.
To owner lookupGet in touch
Interested in the BAG Viewer? We are happy to help with a demo or more information.