โป Based on 2025 (10% VAT rate)
Enter a single VAT-included total amount and this tool precisely splits it into supply value and VAT. It avoids rounding-allocation drift caused by truncating whole-won amounts, so "total = supply value + VAT" always holds exactly, and it also shows a tax-invoice line-item example.
Supply value: โ
Tax amount: โ
Total: โ
Supply value: โ
Tax amount: โ
Total: โ
โป Whole-won truncation method: supply value = floor(total รท 1.1), tax = total โ supply value (always reconciles exactly to the total, with no allocation rounding error).
Supply value is the pure price of goods or services before Value Added Tax (VAT). Adding 10% VAT gives the "total consideration" (or total amount). For example, if the supply value is 100,000 KRW, VAT is 10,000 KRW, and the total is 110,000 KRW. Conversely, if you only received "110,000 KRW including VAT" from a client, you need to split it accurately into supply value and VAT before issuing a tax invoice.
The formula to derive supply value from a VAT-included total is "supply value = total รท 1.1". For a 110,000 KRW total, supply value is 100,000 KRW (110,000 รท 1.1) and VAT is 10,000 KRW (110,000 โ 100,000). In practice, totals like 11,000 KRW may not divide evenly; in that case, truncate the supply value to a whole won (floor(11,000 รท 1.1) = 10,000), then derive the tax as "total โ supply value" so that "supply value + tax = total" holds exactly with no rounding error. Rounding supply value and tax independently can leave a 1-won allocation mismatch, which this calculator avoids.
Often you know only the pure service fee (supply value) and need the final billed amount (total). In that case, use "total = supply value ร 1.1". For example, if a quote just says "service fee 2,000,000 KRW" it may be unclear whether VAT is included, causing disputes โ so it is best to state all three figures: "supply value 2,000,000 KRW + VAT 200,000 KRW = total 2,200,000 KRW".
Tax invoices (including electronic ones) must list supply value and tax amount as separate line items. When issuing an e-invoice via Hometax or an ASP, you must enter supply value and tax accurately; if the system does not auto-split a total, pre-calculating with this tool reduces mistakes. In quotes and contracts, always state all three amounts โ "supply value + VAT = total" โ to avoid disputes with the other party.