Legally Required Invoice Contents: 2026 Checklist for Trades

The legally required invoice contents are set by VAT law, not by your accountant's preferences, and in Sweden that means chapter 17 of mervärdesskattelagen (the VAT Act, 2023:200). A full invoice must carry: the date it was issued; a sequential invoice number from an unbroken series; your VAT registration number; your name and address and the buyer's; the quantity and nature of what you supplied; the date the work was completed or the goods delivered, if that differs from the invoice date; the taxable amount per VAT rate; the rate applied; the VAT amount in kronor; and, where relevant, the reverse-charge reference text. Miss one and the invoice is not merely untidy. It is structurally invalid, your customer's input VAT deduction is exposed, and in 2026 an e-invoicing platform will bounce it back before a human ever reads it.

The legally required invoice contents, line by line

Print this and stick it next to your desk. Every item has a statutory basis, and every item gets checked by validation software before it gets checked by a person.

The invoice number series is a legal object, not a counter

The law asks for a löpnummer based on one or more series that identifies the invoice on its own. Skatteverket expects each series to be unbroken, because a gap is the classic signature of an invoice that was raised, paid in cash and quietly deleted. You may run more than one series — per company, per branch, per year, per system — as long as each is internally sequential and no number is ever reused.

Two rules follow. Never delete a sent invoice; correct it with a credit note that names the original number. And if you switch systems mid-year, either carry the counter across or start a clearly labelled new series (2026B-0001) and write down why. An unexplained jump from 1147 to 1203 is a question you will still be answering years later, because bookkeeping records must be kept until the end of the seventh year after the financial year closed, under bokföringslagen.

Date of supply versus invoice date

These are two different fields carrying different weight. The date of supply — leveransdatum or tillhandahållandedatum — is when you finished the work or handed over the goods. It fixes the tax point, which fixes the VAT period, which is what Skatteverket is actually testing. The invoice date is just the day you got round to raising it.

If both dates are the same you may omit the supply date. If they differ, it is mandatory. Since almost no tradesperson invoices on the day they finish, treat it as always mandatory and make the system print it. Where you take money up front, print the date of the advance payment instead.

Moms broken out per rate

Sweden runs three rates: 25% standard, 12% (food, hotels, restaurant meals) and 6% (books, passenger transport). Trades work is 25% on both labour and materials. The rate does not drop because a job qualifies for ROT — ROT is an income-tax credit for the customer worth 30% of the labour cost, and it changes nothing about the VAT.

You need a per-rate breakdown the moment one invoice carries two rates, which happens more often than owners expect once travel, subsistence or hire items get recharged. Give each rate its own net subtotal, its own VAT line and a total. The VAT amount may be rounded to whole kronor. If you invoice in a foreign currency, the VAT amount must still appear in SEK, converted at the rate applying at the tax point.

The omvänd byggmoms reference text

Reverse charge for construction services catches out more Swedish subcontractors than any other rule, and the invoice text is not decoration. It is a statutory field.

It applies when you sell construction services in Sweden to a buyer who is a business that itself sells construction services other than merely temporarily. Subcontractor invoicing a main contractor: reverse charge. Hiring out labour for construction work: reverse charge. Selling only materials with no installation: not reverse charge. Invoicing a homeowner, a landlord who only lets flats, or a shop: not reverse charge.

When it applies you charge 0 kr VAT, and the invoice must show:

• the buyer's VAT number — mandatory here, not nice to have
• the reference text. Since the 2023 Act the statutory term is omvänd betalningsskyldighet. The older omvänd skattskyldighet still appears on plenty of live invoices, but use the current wording: "Omvänd betalningsskyldighet för byggtjänster. Köparen är skyldig att redovisa mervärdesskatten."
• a net total with no VAT charged, rather than a VAT line showing 0%

Get the direction wrong and you fund the mistake. Charge 25% on a supply that should have been reverse-charged and the buyer cannot deduct it, will refuse to pay it, and you may owe it to Skatteverket until you credit and reissue. Reverse-charge a supply that should have carried VAT and the VAT comes out of a price you already agreed. If you are unsure what the buyer is, ask them in writing and keep the answer on the job.

The F-skatt statement, and why it is not a VAT rule

"Godkänd för F-skatt" is not in the VAT Act at all. It sits in skatteförfarandelagen and concerns preliminary income tax, not moms. The point: if you are approved for F-tax, the payer pays your invoice in full. If you are not, the payer must withhold tax at source and pay employer contributions on your labour. That is why a main contractor will not touch an invoice that is silent on it.

The statement only does its job if the document also carries both parties' name and address and your organisation number or personnummer. So the safe line on every invoice and every quote is "Godkänd för F-skatt" next to your organisation number. The payer is also expected to verify your status against Skatteverket's register rather than trust your footer, so keep the approval live. A lapsed F-tax approval turns every open invoice into a withholding problem for your customer.

When a förenklad faktura is allowed

A simplified invoice is a real, legal, shorter invoice. It is not a receipt and it is not permission to be vague.

You may use one when the total including VAT does not exceed 4 000 kr, or where commercial practice or technical conditions make a full invoice impractical, or for a corrective document such as a credit note. Check the current threshold at skatteverket.se before you configure it, because amounts get revised.

It must still contain the date of issue, identification of the seller, identification of the type of goods or services, and the VAT amount or the information needed to calculate it. A credit note must additionally give a specific and unambiguous reference to the original invoice.

You may not use a simplified invoice for:

• cross-border supplies of goods or services to another EU country
• distance sales
• any supply where the buyer is liable for the VAT — so never for omvänd byggmoms, whatever the amount

One practical warning. Plenty of main contractors' accounts payable will reject a simplified invoice on principle, because their system needs a purchase-order reference and a supply date to match it. Legal and accepted are not the same thing.

What makes an accountant reject your invoice

These are the defects that actually come back, roughly in order of frequency:

• No supply date. The bookkeeper cannot place it in the right VAT period.
• "Enligt överenskommelse" as the whole description. Nature and extent are required. Write "Byte av elcentral, 3 nya uttag, felsökning jordfel, 11 h" and nobody asks twice.
• Reverse charge with no buyer VAT number or no reference text. Automatic return.
• A credit note that names no original invoice. It reconciles against nothing.
• Two VAT rates, one net total. Unpickable.
• Foreign currency with no SEK VAT amount. Required, at the tax-point rate.
• ROT invoices with labour and materials in one line. Not a VAT-Act defect, but Skatteverket's payout request needs the labour cost separately, plus the property designation or the housing association's organisation number and the flat number. Get it wrong and the claim fails after you have already discounted the invoice.

Worth knowing if you are ever challenged: EU case law (Barlis 06, C-516/14, and Senatex, C-518/14) holds that a tax authority should not refuse an input VAT deduction on purely formal invoice defects when it already has the information to verify the substance, and that a corrected invoice can take retroactive effect. That is a defence, not a filing strategy. It costs professional fees to run.

Why this bites harder in 2026

A defective invoice used to be a human problem. Someone in accounts payable emailed you, you fixed it, you got paid a fortnight late. Structured e-invoicing removes the human. A Peppol BIS Billing 3.0 or BEAst message is validated against a schema at the access point. If the supply date is absent, or the reverse-charge code contradicts the VAT total, the message is rejected at the door and you may never see a useful error.

Invoices to Swedish public-sector bodies have had to be e-invoices since 1 April 2019 under lag (2018:1277). The EU's VAT in the Digital Age package clears the way for member states to mandate domestic B2B e-invoicing, with structured invoicing and digital reporting for cross-border trade following later this decade. Swedish authorities have been examining a domestic mandate; check the current position with Skatteverket and DIGG rather than trusting a blog. The direction of travel is not in doubt.

The response is dull and effective: stop hand-building invoices in a spreadsheet or a word processor. Set the mandatory fields once, in a system that refuses to send an invoice without a supply date, owns the number series so it cannot break, flags reverse charge from the customer record, and splits ROT labour out automatically. OdinTask does that because it was built for Swedish trades, but the principle holds whatever you use. The field checks belong in the software, not in your memory at nine on a Sunday night.

Reading this from outside Sweden

The shape of the rules is the same across most VAT and GST systems, because they descend from the same EU VAT Directive or from similar logic. The details differ.

If you work in the UK the trap is identical in spirit: a domestic reverse-charge invoice under the CIS rules that fails to state the customer must account for the VAT, and fails to show the rate or amount to be accounted for, is defective. Same failure mode, different statute.

The five-minute audit

Open your last three sent invoices and check, in order. Is there a supply date. Is the VAT number in SE-format with the 01 suffix. Does every reverse-charge invoice carry the buyer's VAT number and the reference text. Is the description something a stranger could audit. Do the numbers run unbroken. If any of the five fails it is a template problem, not a one-off — fix the template today and the next hundred invoices are clean.

Tired of checking by hand? Start a free trial and set the fields once. More on invoicing and admin on the OdinTask blog.