Bokföringslagen

Developer-facing compliance reference for building Swedish accounting software. This skill answers questions about what the law requires so you can verify your implementation is correct.

How to use this skill

This skill has a router structure. The SKILL.md contains the most critical rules you need constantly. Detailed reference material lives in references/. Read the relevant reference file when you need depth on a specific area.

Reference files

File	When to read
references/bfl-bfnar.md	Questions about bokföringslagen (BFL), BFNAR, K1/K2/K3, ÅRL, bokföringsskyldighet, verifikationer, arkivering, räkenskapsår, systemdokumentation
references/skatteverket.md	Questions about moms/VAT, arbetsgivaravgifter, skattedeklaration, F-skatt, skattekonto, Skatteverket API integration, AGI
references/bas-kontoplan.md	Questions about BAS chart of accounts, account numbering, account classification, mapping transactions to accounts
references/sie4.md	Questions about SIE file format, import/export, data exchange between systems
references/changes-2025-2026.md	Questions about recent or upcoming regulatory changes, new rules, updated amounts/thresholds

Read multiple reference files when a question spans domains (common).

Core principles (always in context)

Bokföringsskyldighet (BFL 2 kap)

Every aktiebolag, handelsbolag, and ekonomisk förening is bokföringsskyldigt. Enskild firma with fysisk person is bokföringsskyldig. The obligation cannot be delegated: even if someone else does the bokföring, the företagare is legally responsible.

Löpande bokföring (BFL 5 kap)

• Affärshändelser shall be bokförda in both grundbok (journal) and huvudbok (ledger)
• Kontanta in/utbetalningar: senast nästa arbetsdag
• Övriga affärshändelser: så snart det kan ske. BFNAR 2013:2 allows senareläggning if verifikationerna are kept ordered meanwhile (3.5): up to 50 days after the end of the month (3.6); 50 days after the end of the quarter if nettoomsättning normalt ≤ 3 MSEK (3.7); 60 days after räkenskapsårets end if normally ≤ 50 verifikationer (≤ 250 affärshändelser) and ≤ 1 MSEK (3.8); enskild näringsidkare within the 3.8 limits and without EU trade: until the inkomstdeklaration due date (3.9). Kontanta in/utbetalningar must still be registered in registreringsordning by next arbetsdag (certified kassaregister: 50 days after month-end, 3.10)
• Every affärshändelse requires a verifikation

Verifikationer (BFL 5 kap 6-7§)

A verifikation must contain:

1. Datum för affärshändelsen
2. Datum för verifikationen (if different)
3. Vad affärshändelsen avser (description)
4. Belopp
5. Motpart (when applicable)
6. References to underlag (kvitto, faktura etc.)
7. Verifikationsnummer (unique, in unbroken series per räkenskapsår)

Verifikationer must be numbered in a systematisk serie without gaps. If a verifikation is corrected, the original must be preserved and the correction linked.

Rättelse (BFL 5 kap 5§)

A rättelse of a bokföringspost must be documented so that both the original and the corrected post are visible. You cannot simply overwrite. Implement as: new correcting verifikation referencing the original.

Arkivering (BFL 7 kap)

• Räkenskapsinformation must be preserved for 7 years after the end of the calendar year the räkenskapsår ended
• Since 1 July 2024: no requirement to keep paper originals after digitization (BFL 7 kap 6§ updated, SFS 2024:342)
• Digital storage must ensure the information cannot be altered (immutability requirement). Electronic documents are kept in the format and with the content they had when received or compiled (BFL 7 kap 1§ 3 st)
• Stored in Sweden (BFL 7 kap 2§). Electronic räkenskapsinformation may be stored in another EU country, or a non-EU country with equivalent mutual-assistance instruments, if the location is reported to Skatteverket, Skatteverket/Tullverket get immediate electronic access, and a printout can be made immediately in Sweden (BFL 7 kap 3a§). Otherwise a permit from Skatteverket is needed (7 kap 4§). Paper verifikationer may only be kept abroad temporarily (7 kap 3§)

Momssatser (current as of 2026)

• 25% - standard rate (most goods and services)
• 12% - food (outside the temporary 6% period), restaurants/catering, hotels/camping, konstverk, certain repairs (bikes, shoes, clothes)
• 6% - books, newspapers, public transport, cultural/sports events, dance events (danstillställningar, from 1 July 2026), livsmedel (temporarily from 1 April 2026 to 31 Dec 2027)
• 0% - certain financial services, healthcare, education, insurance

IMPORTANT: From 1 April 2026, livsmedel drops from 12% to 6% (tillfälligt, Prop. 2025/26:55). Restaurang/servering stays at 12%. The reversion to 12% from 1 Jan 2028 is already enacted (SFS 2026:119). Software must handle both dates.

Fakturakrav (ML 17 kap)

A momsregistrerad seller's faktura must contain:

1. Utfärdandedatum
2. Löpnummer (unique, unbroken series)
3. Säljarens momsregistreringsnummer
4. Köparens momsregistreringsnummer (if reverse charge or EU)
5. Säljarens och köparens namn och adress
6. Varans/tjänstens art, omfattning, mängd
7. Datum för leverans/tillhandahållande
8. Beskattningsunderlag per skattesats
9. Tillämpad skattesats
10. Momsbelopp
11. Eventuell hänvisning till undantag

Förenklad faktura (max 4000 SEK inkl moms) has reduced requirements.

Key thresholds (2026)

• Prisbasbelopp: 59 200 kr
• Inkomstbasbelopp: 83 400 kr
• Inventarier av mindre värde: halvt prisbasbelopp = 29 600 kr (exkl moms)
• Förenklat årsbokslut: omsättning normalt < 3 MSEK
• Kontantmetod: omsättning normalt < 3 MSEK
• Revisionspliktig (AB): minst 2 av 3: >3 anställda, >1.5 MSEK balansomslutning, >3 MSEK nettoomsättning (two consecutive years)

System documentation (BFNAR 2013:2 kap 9)

Bokföringssystem must have:

1. Systemdokumentation: describes the system, how it works, its controls
2. Behandlingshistorik: log of changes, who did what, when

Your software must produce or support both. This is not optional.