Noord-Holland · Municipality

Prefab home extension in Amsterdam

An extension in Amsterdam starts with your home and its surroundings. Use local housing figures as context, compare usable space gained and consider access, existing foundations and the remaining garden. Connect those choices with your own budget and value scenario below.

Design your extension Calculate added space

Concept of a shared meal in a spacious kitchen and dining area

Design impression · not a completed local project

486,769homesCBS · 2025

€518,000average WOZ assessed valueWOZ · 01-01-2024

12%single-family homesCBS · 2025

GM0363 · CBS 2025

Housing in Amsterdam: the figures

These figures describe the area, not your individual home. The table uses CBS data for 2025. WOZ assessed values refer to 1 January 2024 and are not current sale prices.

Housing profile · CBS 2025
Measure	Amsterdam
Residents	934,526
Dwelling stock	486,769
Average WOZ value per dwelling	€518,000
Single-family homes	12%
Mid-terrace homes	9%
End-of-terrace homes	2%
Semi-detached homes	1%
Detached homes	1%
Apartments / multi-family homes	88%
Owner-occupied homes	31%
Built within the previous ten years	11%
Residents per km² of land	4,968
Land area	18,812 ha
Water area	5,553 ha

Housing type percentages refer to total dwelling stock. Rounding or unknown values may prevent them adding up to 100%. Missing data does not mean zero. Areas describe the whole region, not garden or building plot sizes.

What do these figures mean for your plans?

CBS records 486,769 homes in Amsterdam. Single-family homes account for 12% and owner-occupied homes for 31%. This provides local context; it does not establish the space, ownership situation or extension possibilities at your home.

Mid-terrace homes are the largest of the four listed single-family categories at 9%. For a terraced home, pay particular attention to rear garden access: measure the passage, discuss lifting work and record the boundary connection. A site visit establishes what applies to your home.

Population density is 4,968 residents per km² of land. In a densely built area, review truck and crane access, temporary work space and arrangements with neighbours early. Density is an area statistic; it does not prove that your street is difficult to access.

11% of homes were built in the ten years before the CBS reference date. This distribution is not a building inspection. Your extension depends on the existing wall, foundations, floor level and services: have their connections designed in advance.

Ground & foundations

A sound plan starts below ground.

What ground lies under your building position in Amsterdam? A place name or property value cannot reliably answer that. Use subsurface data to prepare investigations, and base the foundation choice on measured ground layers, loads and the existing house.

This page does not establish a measured ground profile or soil type for your plot in Amsterdam.

Ground conditions: what to investigate
If this is found…	Discuss…
Sand layers	Density, thickness and depth of suitable layers; surface sand does not establish a suitable foundation.
Clay or peat	Compressibility, water conditions and possible differential settlement between house and extension.
Fill or former buildings	Variable layers, debris, old foundations and any additional ground investigations.
Groundwater	Seasonal variation, excavation methods and suitable damp protection.

BRO GeoTOP

BRO GeoTOP describes subsurface conditions in 100 × 100 metre cells and 0.5 metre layers. It provides a regional starting point; street or building assessments need additional detail. A model therefore does not replace investigation for your foundation design.

Explore subsurface data at BROloket

Garden land is different from living space.

An extension adds indoor space while using garden area. Retain room for daylight, a terrace, greenery, maintenance and drainage. If buying additional land, assess ownership, permitted use and its price separately. Property value per m² is not a land price.

Read about foundations and the existing house

Space & building budget

What does another metre give you?

First compare the space you can actually use. These examples assume a rectangular extension, two side walls and one front wall of 30 cm. The connection to the house has no rear wall in this simplified calculation.

Four sizes compared · illustrative calculations
External dimensions	External area	Estimated internal area	Base amount at €2,750/m²
4 × 3 m	12 m²	9.18 m²	€33,000
5 × 3 m	15 m²	11.88 m²	€41,250
6 × 3 m	18 m²	14.58 m²	€49,500
6 × 4 m	24 m²	19.98 m²	€66,000

The base amount is external area × an illustrative rate of €2,750 including VAT. It is not a quotation, local market rate or total price. Foundations, structural opening, transport, options and complete finishes may be additional. Internal area is not a certified measurement.

Explore all parts of a building budget More about measuring living space

Value per m²

Value per square metre: use your own home.

What is another square metre worth in Amsterdam? That depends on the home, location, quality and sales market. Divide your home’s estimated current market value by its measured living area for a starting point. Then choose your own assumption for the new space.

We do not convert average WOZ values into a local sale price per m². Comparable sale prices and their corresponding floor areas have not been established here. The calculator starts with illustrative amounts that you can change.

MORE SPACE, POSSIBLE ADDED VALUE

What could your extension add?

Explore added living area and a possible value effect. The prefilled figures are examples; adjust them to your home.

Current home value (€)

Current living area (m²)

Extension width (cm)

Extension depth (cm)

Assumed wall thickness (cm)

Total building budget incl. VAT (€)

Include foundations, the wall opening, transport and complete finishes in your budget. The configurator amount is not a complete building budget.

Enter the added living area yourselfFor example, use the added area from a measurement report.

What share of the current price per m² will you use?

These are three example scenarios, not an evidence-based forecast. Added square metres are not automatically worth as much as existing ones.

YOUR CALCULATION SCENARIO

Possible increase in value€52,500at your selected assumption of 80%

External extension area: 18 m²
Added living area in this scenario: 14.58 m²
Living area after the extension: 114.58 m²
Current average value per m²: €4,500
Home value after extension in this scenario: €502,500
Total building budget entered: €70,000
Value effect minus building budget: -€17,500

A negative difference means the calculated value effect is below the building budget. Enjoyment of your home, interest and other selling costs have not been valued here.

Compare three example scenarios
Assumed share of value per m²	Value effect	Value after extension
60%	€39,400	€489,400
80%	€52,500	€502,500
100%	€65,600	€515,600

This is a scenario, not a valuation or guaranteed increase. The price per m² is home value divided by existing living area. The model multiplies this price by added living area and your chosen percentage. Market changes, garden loss and project-specific quality are not calculated separately.

How do we estimate the extra square metres?

The automatic estimate deducts two side walls and one front wall from a rectangular extension. No rear wall is deducted. This simplifies the connection to the house; the actual wall construction and a measurement report may produce different areas. A garden room or detached unit does not automatically count as living area of the house.

More about internal and external dimensions Continue with your design

Three figures to keep separate
Figure	Meaning
WOZ value per dwelling	An area average with a historic valuation date; not the value of your extension.
Property value per m²	A starting point based on your home’s market value and floor area; new space may be valued differently.
Land price per m²	The price of a specific plot with particular uses and rights; not established here.

Your preparation

From local insight to a concrete plan.

Make the quotation request for your home in Amsterdam as complete as possible. This information helps establish requirements and identify what still needs investigation.

Home & wishes

Collect existing drawings, construction year, rear elevation photos and desired internal dimensions. Note whether you need kitchen space, a work area or a bedroom.

Plot & access

Measure garden access and record trees, fences, outbuildings, level differences and crane space. Review ownership and any access arrangements.

Rules & investigations

Complete the official Dutch permit check for the exact address and plan. Discuss the structural information, ground data and additional investigations required.

Complete comparison

Ask which work and costs are included, who handles preparation and which assumptions remain open. Compare quotations for the same dimensions and finishes.

Open the official permit check

Rules may differ by address and design. This page does not establish that your extension is exempt from a permit.

Discuss your plans

Home ideas & services

What would you like to create in Amsterdam?

Compare six possibilities and see what to investigate for each. The figures for Amsterdam above provide local context; suitability depends on your home, plot and intended use.

Home ideas & services
What would you like to build?	What to consider at your home	Understand more before choosing.
Prefab extension	Have the existing rear wall, foundations and floor level surveyed. Draw the dining table, seating and walking routes within the internal dimensions to assess usable added space. For a terraced home, discuss access alongside or over the house.	Read more about Prefab extension
Living conservatory & garden room	First decide whether you want heated living space or a sheltered seasonal room. Then consider sun orientation, shade, ventilation and privacy. A glazed extension does not automatically qualify as living area because of its name; have its use and construction assessed.	Read more about Living conservatory & garden room
Family care home	Start with the resident: accessibility, bathroom, independence and the path to the main house. Have the intended use and rules assessed for the exact address. Include the length and capacity of water, electricity and drainage connections in the preparation.	Read more about Family care home
Detached garden building	Define whether the unit will be an office, hobby room, guest space or independent dwelling. This determines the services required and the assessment of its use. Measure the distance to the main house, the installation route and maintenance clearance around the unit.	Read more about Detached garden building
Two-storey extension	Space on two levels requires a coherent structural design. Have loads, foundations, stability, connections to the existing house and access to the upper level designed together. An existing extension is not automatically suitable to support another floor.	Read more about Two-storey extension
Prefab utility room	Use the actual dimensions of the washing machine, dryer, storage cupboards and doors. Discuss ventilation, noise, electricity, water and drainage at the required positions. In a compact utility room, wall thickness and awkward door swings can significantly affect usable space.	Read more about Prefab utility room

Explore local preparation Nationwide directory

In the area

Explore more in Amsterdam.

Explore the listed districts in this municipality. Each has its own CBS figures; the general technical guidance helps you prepare investigations at your home.

Noord-Holland

Figures with a source.

Source: CBS, Key figures for districts and neighbourhoods 2025 (86165NED), updated 25 June 2026 and retrieved 13 September 2026. Dwelling stock and types: 1 January 2025. WOZ valuation date: 1 January 2024. Area code: GM0363. Provinces and town search names are linked through CBS Towns in the Netherlands 2026 (86312NED).

CBS: view original area statistics ↗TNO: GeoTOP and appropriate scale of use ↗Kadaster: how to assess property value ↗NVM: floor area measurement guidance ↗

The directory contains 342 municipalities and 3,158 residential districts selected by dwelling stock. Town names also lead to their municipality. A location page is not a branch or a confirmation of availability; access, scheduling and feasibility need to be agreed for your address.

YOUR NEXT CHAPTER

All that's left
is to dream.

Choose dimensions, compare finishes and save your design. Start a conversation about your extension with a clear picture and an explained cost estimate.

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