Reverse charge VAT for construction: how to invoice right

Reverse charge VAT (in Sweden, omvänd byggmoms) is a rule that flips who accounts for the VAT on a construction job. Normally you add VAT to your invoice, collect it from the customer, and pay it to the tax authority. Under reverse charge you invoice with no VAT at all, and the customer accounts for the VAT themselves — reporting both the output VAT and their own input VAT on the same return, so the two usually net to zero. It exists to stop VAT fraud in construction supply chains, where a subcontractor could collect VAT and vanish before handing it over. In Sweden it applies when you sell building services to a customer who also sells building services; the UK runs the equivalent CIS domestic reverse charge, in force since 1 March 2021. Get it wrong and you either pay the taxman money you never owed, or leave yourself holding a VAT bill you can no longer pass on.

When reverse charge VAT applies: the buyer's status is the whole test

The mistake most tradespeople make is thinking reverse charge depends on what they sell. It does not. It depends almost entirely on who they sell to. In Sweden two conditions must both be true:

• The work is a construction service (byggtjänst) — building, ground works, installation, electrical, plumbing, painting, demolition, scaffolding erected with labour, and similar site work.
• The buyer is a business that, more than occasionally, sells construction services onward — another trades firm, a main contractor, or a developer that resells building work. Their own VAT status and whether they on-sell is what triggers the rule.

So the same one-van electrician can be in two different worlds on the same week. Wiring a factory directly for the company that owns and uses it: charge VAT as normal. Wiring the same job as a subcontractor to the main contractor who is reselling the whole build: reverse charge, no VAT. The service is identical. The customer is not.

Things that fall outside reverse charge in Sweden: pure sales of materials with no installation, architecture and pure design or consultancy, and most cleaning. In the UK the test is shaped differently — the service must be reportable under the Construction Industry Scheme (CIS), both parties must be VAT-registered, and the customer must not be an end user (the business that will actually use the finished building rather than resell the work). The common thread across both countries is the same: reverse charge is for business-to-business links in a construction chain, never for the person who ends up living in or occupying the result.

The one question that settles it: ask the buyer

You cannot always tell a reselling contractor from an end user by looking at the job. The fix is a written question, kept on file. Before you invoice a business customer, confirm two things in writing:

• Their VAT registration number (in Sweden, their momsregistreringsnummer; in the UK, their VAT number).
• Whether they are reselling your work as part of a construction supply, or are the end user of it.

Their answer decides the VAT treatment, and the email or signed statement is your evidence if the tax authority ever asks why you left VAT off. If a customer refuses to confirm their status, treat that as the warning sign it is.

What goes on a reverse charge invoice

A reverse charge invoice looks almost like a normal one, with three deliberate differences. You still itemise the work, you still show the net amount, and the customer still pays that net amount. What changes is the VAT line and the wording.

In Sweden the required text is a clear reference such as "Omvänd skattskyldighet för byggtjänster" (reverse charge for construction services). In the UK, HMRC wants wording to the effect of "Reverse charge: customer to account for VAT to HMRC" and the VAT rate that would have applied. Leave the buyer's VAT number off, or leave the statement off, and the invoice is technically invalid — a careful accountant on the other side will bounce it, and your payment stalls while you reissue.

This is exactly the kind of rule a job system should handle for you rather than leave to memory. In OdinTask you flag the customer as reverse-charge once, and every invoice from that job card drops the VAT, carries the buyer's VAT number and the correct statement automatically, then syncs to Fortnox or Visma with the right VAT code. It removes the most common failure, which is a technician raising a quick invoice with 25% VAT on it out of habit.

The cash-flow trap nobody warns you about

Here is the part that surprises subcontractors in their first reverse-charge year. Under normal VAT, the VAT you collect from customers sits in your bank account for weeks before you remit it. It is not your money, but it behaves like a float, and plenty of firms quietly lean on it. Under reverse charge you never collect that VAT, so the float disappears overnight.

Worse, you still pay VAT on your own materials, fuel and tools. If most of your sales are reverse-charge but your purchases are not, your input VAT will regularly exceed your output VAT, and you move into a permanent VAT repayment position — the tax authority owes you, rather than you owing them. That is fine, but it means real cash is tied up waiting for refunds. Two practical moves:

• Do not spend VAT you never collected. If you were used to a VAT buffer in the account, build a real cash buffer to replace it. The invoice total is now the net figure, and that is all that is landing.
• Consider filing VAT monthly rather than quarterly. If you are consistently owed refunds, shorter periods get your cash back faster. In Sweden you can ask Skatteverket to change your reporting period; in the UK you can apply to HMRC for monthly returns.

Three mistakes that cost real money

Every reverse-charge error falls into one of three buckets, and each has a price.

1. Charging VAT when reverse charge applies. The buyer cannot reclaim VAT you were not entitled to add, so they will refuse to pay it and ask for a corrected invoice. Until you reissue, the whole invoice can sit unpaid. Annoying, but recoverable.
2. Using reverse charge when it does not apply. This is the expensive one. If the customer was actually an end user, or not a reselling business, you were supposed to charge VAT — and the tax authority will still want it. You now owe VAT you never collected, out of your own margin, plus possible interest. This is why the written buyer confirmation matters.
3. Right treatment, wrong invoice. Correct VAT handling but a missing VAT number or missing reverse-charge statement makes the invoice non-compliant. It delays payment and can create problems for the buyer's own VAT deduction, which sours the relationship you want to keep.

Sweden, the UK, and everywhere else

The idea is the same across borders; the trigger differs. Sweden keys off whether the buyer is a construction-services reseller. The UK keys off the CIS scheme, VAT registration on both sides, and the end-user test, with a formal way for end users and intermediaries to opt out by notifying in writing. Not every country has a construction reverse charge at all — under standard GST systems in New Zealand and Australia, domestic building work is generally invoiced with GST in the normal way, so the reverse-charge questions above do not arise. If you work across markets, the rule is simple: never assume the VAT treatment travels with you. Check the local position before the first invoice, not after.

Reverse charge is not complicated once you accept that it is a question about your customer, answered before you invoice, and then applied consistently. The firms that get burned are the ones improvising it invoice by invoice.

If your invoicing is where these rules go wrong, fix that first. Start a free 14-day trial of OdinTask to set a customer's VAT treatment once and have every invoice follow it, or read the rest of the blog for the workflows around quoting and getting paid.

This article is general information for trades businesses, not tax advice. VAT rules and rates change — confirm your position with Skatteverket (skatteverket.se), HMRC, or your accountant before you invoice.