Denmark Construction Industry Tax Guide (Bygherreordning, A-skat)

Danish construction industry tax obligations — A-skat withholding and liability for building owners, reverse charge VAT, foreign contractor verification via RUT, and subcontractor chain compliance.

The Danish construction industry faces unique tax rules designed to combat undeclared work and tax evasion. Building owners (bygherrer), main contractors, and subcontractors all have specific obligations under the Kildeskatteloven (KSL), the VAT Act, and the RUT Register (Register for Udenlandske Tjenesteydere). All amounts in Danish kroner (DKK). For related reading, see our starting a business guide →, VAT registration guide →, and hiring employees guide →. For construction businesses involved in public-private partnerships, see our Public-Private Partnership Guide →. For foreign contractors and PE risk assessment, see our Permanent Establishment Guide →.

A-skat Withholding in Construction — Who Owes What

The core tax issue in construction is withholding of A-skat and AM-bidrag. Any person or entity making payments that constitute A-income (employee income) must withhold tax and report through eIndkomst. In construction, the line between employees (lønmodtagere) and self-employed contractors (selvstændige) is frequently disputed, and the consequences of misclassification are severe.

Main Contractor and Subcontractor Chain Liability

If you hire a subcontractor — The subcontractor is responsible for its own workers' A-skat and AM-bidrag, assuming they are genuinely self-employed or have their own employees.
Chain liability (hæftelse): If a subcontractor fails to withhold or pay A-skat/AM-bidrag, the main contractor (and potentially the building owner) can be held personally liable for the unpaid amounts under KSL §69, stk. 1. This liability applies if the payer knew or should have known that the subcontractor would not fulfil its obligations.
Reclassification risk: If workers provided by a subcontractor are found to be in an employment relationship with the main contractor or building owner (e.g., they take instructions from your project manager, use your tools, work set hours), the main contractor/building owner is treated as the employer and must have withheld A-skat and AM-bidrag. Back taxes, penalties, and interest will apply.

Practical Protection Measures

Verify subcontractor registration: Check that each subcontractor has a valid CVR number and is registered for A-skat, VAT, and AM-bidrag at Erhvervsstyrelsen.
Request documentation: Obtain the subcontractor's G-certificate (service certificate) or EIFO service voucher confirming their tax registration status.
Contractual safeguards: Include clauses requiring subcontractors to certify tax compliance and indemnify you for any liability arising from their non-compliance.
Monitor foreign contractors via RUT: Foreign service providers must register in the RUT register (Register for Udenlandske Tjenesteydere) before starting work in Denmark. Verify their registration at virk.dk.
Retain records: Keep contracts, invoices, RUT verifications, and correspondence for at least 5 years to demonstrate due diligence if SKAT audits the chain.

Reverse Charge VAT (Omvendt Betalingspligt) for Construction

Denmark applies reverse charge VAT (omvendt betalingspligt) for most B2B construction services. This means the buyer (not the seller) accounts for the VAT on the transaction. Key rules:

Applies to: Construction services between VAT-registered businesses, including building, renovation, repair, demolition, and installation work. Also applies to the supply of construction materials if included in the service contract.
Who is affected: Any business providing construction services to another business. Private consumers are not affected — they pay VAT at the standard 25% rate included in the price.
How it works: The supplier invoices without VAT (marked "reverse charge / omvendt betalingspligt"). The buyer calculates the VAT on the transaction (25% of the amount), reports it as both output VAT and input VAT on their own VAT return — resulting in a net zero cash flow effect for the buyer.
Documentation: Invoices must clearly state "reverse charge" or "omvendt betalingspligt" and include both parties' VAT numbers. Incorrect invoicing can result in penalties.

RUT Register for Foreign Service Providers

Foreign (non-Danish) businesses providing construction services in Denmark must register in the RUT register (Register for Udenlandske Tjenesteydere) before starting work. This register is administered by Erhvervsstyrelsen and serves as a transparency tool for tax authorities.

When to register: Before starting the first construction project in Denmark. Registration is free and can be done online at virk.dk.
Information required: Company details (name, address, foreign registration number), Danish contact person, expected work period, description of services, and the Danish customer's CVR number.
Updates: Must notify Erhvervsstyrelsen of any changes (e.g., extended work period, new customer).
Consequences of non-registration: Fines and potential liability for unpaid taxes. Danish customers are advised to verify RUT registration before engaging foreign contractors.
Compliance check: Danish customers can search the RUT register at virk.dk to verify a foreign contractor's registration. This is a recommended due diligence step.

Employer Registration and Reporting

Construction businesses with employees must register as an employer and comply with ongoing reporting obligations:

Registration: Register via Erhvervsstyrelsen within 8 days of becoming liable for A-skat and AM-bidrag.
eIndkomst reporting: All wages, benefits, and tax withholdings must be reported to eIndkomst no later than the day after payment. This includes both Danish and foreign employees working on Danish construction sites.
Filing frequency: Semi-annual A-skat returns due March 1 (for July-December) and September 1 (for January-June). Large employers (AM-bidrag ≥ 250,000 DKK/year or A-skat ≥ 1,000,000 DKK/year) may have monthly filing obligations.
Employees working short-term in Denmark: Even short-term construction projects trigger A-skat/AM-bidrag obligations if the workers are considered Danish-tax-resident or perform work physically in Denmark. Special rules apply for posted workers under EU social security coordination.

For more on employer obligations, see our hiring employees guide → and AM-bidrag guide →.

FAQs

What is the bygherreordning in Danish tax law?

The term bygherreordning can refer to two different things: (1) in tax law, it refers to the building owner's liability for A-skat/AM-bidrag in the subcontractor chain (KSL §69); (2) in work environment law, it refers to the building owner's obligation to coordinate safety on construction sites (Arbejdstilsynet). This guide addresses the tax aspects.

As a building owner, am I liable if my subcontractor doesn't pay A-skat?

Yes, potentially. Under KSL §69, stk. 1, you can be held liable if you knew or should have known that the subcontractor would not fulfil its tax obligations. Perform due diligence: verify CVR registration, request G-certificates, and check RUT registration for foreign contractors. Document all checks.

Does reverse charge VAT apply to construction work for private homeowners?

No. Reverse charge VAT only applies to B2B transactions. If you provide construction services to a private homeowner, you must charge 25% VAT and report it in the normal way. The reverse charge only shifts the VAT obligation to the buyer when the buyer is a VAT-registered business.

Do I need to register in RUT for a one-day construction job in Denmark?

Yes. The RUT registration requirement applies from the first day of work in Denmark, regardless of the duration or size of the project. Registration is free and takes approximately 15 minutes online.

What happens if SKAT determines my subcontractor's workers are actually my employees?

You will be liable for unpaid A-skat, AM-bidrag, interest, and penalties for the entire period. SKAT may also impose a classification penalty of up to the unpaid tax amount. The workers themselves may be reassessed for unpaid personal taxes. This risk is especially high with foreign subcontractors. Conduct a genuine assessment of the working relationship before engaging workers through intermediary companies.