Home extension costs per m2 in 2026
A practical 2026 price guide for home extensions in the Netherlands, with realistic m2 ranges and the main reasons quotes differ.
Online price guides often mix shell-only figures, turnkey projects and older data. That makes extension budgets hard to compare.
Use the ranges below as a first filter. The final price still depends on foundation, glazing, finish level, access and whether drawings or permits are needed.
Realistic 2026 ranges
For a bespoke rear extension, a realistic 2026 range is roughly EUR 1,800 to EUR 3,500 per m2. Straightforward projects with standard finishes sit near the lower end; complex glazing, difficult access or premium finishes push the price higher.
Second-storey extensions and roof additions vary even more because structure, stairs and wet rooms can change the scope dramatically.
- Bespoke extension: typically EUR 1,800 to EUR 3,500 per m2.
- Second-storey extension: broad range due to structure and access.
- Prefab extension: predictable when the shape and finish are standard.
- Conservatory or bay window: highly dependent on glazing and detailing.
Why quotes differ
Two extensions of the same size can have very different prices. Foundations, steelwork, rooflights, sliding doors, insulation and finish level all change the total.
Also check whether VAT, permit costs, drawings, structural calculations and interior finishing are included. These items are often where quotes become hard to compare.
How to use a m2 price
A m2 price is useful for early budgeting, but it should not replace a scoped quote. Ask what is included, what is excluded and which assumptions the contractor made.
At Aanbouw 24/7 we translate the first idea into a clear scope before giving a fixed-price proposal.
Summary
A m2 price is a useful starting point, not the final answer. Compare quotes on scope, foundation, finish and exclusions before judging the price.
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