Invoice Requirements in South Korea: Legal Rules for 2026

South Korean VAT (부가가치세) relies heavily on electronic tax invoicing through the National Tax Service (NTS) ecosystem for many B2B flows. Corporate buyers expect structured issuance that their ERP can ingest; a casual PDF may not qualify as the statutory evidence chain. 2026 operations should treat invoice data as return-ready, not “finance will fix it later.” This overview is general information, not legal advice—confirm zero-rated exports, services to non-residents, and simplified regimes with the NTS or your Korean tax adviser. Chaebol-style shared service centres often impose extra GL codes on e-tax exports—negotiate fields before you integrate APIs.

Required fields

Electronic tax invoices (e-tax invoices) and related documents carry supplier business registration number, buyer identifiers where required, serial identifiers, dates, line descriptions, taxable value, VAT rate and amount, and totals. Credit notes must reference original issuances and adjust VAT consistently. English summaries may appear for foreign parents but statutory Korean fields govern compliance.

Tax rules (VAT/GST/sales tax rates)

The standard VAT rate is 10%. Zero-rated exports and certain foreign services depend on place of supply and documentation. Exempt supplies must not show recoverable VAT improperly. Mixed transactions need line clarity so buyers can reconcile deductions. Head-office / branch billing must mirror business registration hierarchies so e-tax identifiers match withholding receipts and VAT returns. Free-trade-zone adjacent logistics can create edge cases for place of supply—archive contracts beside e-tax XML when auditors trace services across borders.

Language requirements

Korean is mandatory for official e-tax fields and NTS reporting. English may supplement contracts but cannot replace Hangul labels required on statutory outputs.

Digital invoicing rules

Issuance typically flows through NTS-connected software or service providers—archive XML/JSON, PDF renditions, and acknowledgement logs. Immutable storage supports VAT audits and transfer pricing reviews that reference invoice trails. ERP postings should include e-tax serial keys in memo fields so finance shared services can reconcile AP batches without opening raw JSON daily. Time-zone stamps matter for month-end closes when HQ sits outside Korea—use consistent UTC logging internally, local presentation externally.

Penalties

The NTS may impose penalties and surcharges for late issuance, omissions, or incorrect VAT linked to non-compliant documents. Customers may block payment when e-tax data fails validation; contractual SLAs can stack on top of statutory penalties when issuance misses buyer cut-offs.

In practice, treat invoice issuance as part of your month-end close: reconcile e-tax serials to revenue journals before group consolidation. Intercompany recharges should carry clear Korean descriptions so local auditors are not forced to translate English memos under deadline pressure. Run quarterly template reviews whenever NTS notices change rates, codes, or withholding interactions.

Document escalation paths when e-tax APIs fail during month-end; tax law timelines rarely forgive vendor outages. For conglomerates, map each business unit’s registration numbers to template libraries so shared services cannot pick the wrong legal entity header. During M&A integrations, run parallel e-tax issuance tests in a sandbox environment before cut-over weekends to avoid blanketing customers with rejected documents. Keep a dated screenshot log of successful e-tax submissions for high-risk quarters when NTS maintenance windows overlap your close calendar.

Template link

Use our South Korea invoice template alongside your e-tax solution for human-readable layouts. Read the invoice tax compliance guide and tax rate lookup tool. Official references include the National Tax Service (English) and Hometax. Join InvoiceQuickly early access to coordinate Korean VAT invoicing with your APAC footprint.