v0.10.0How to use
- Choose whether the amount you enter is the net amount (before VAT) or the VAT-inclusive total.
- Enter the amount. The rate is 10% by default and can be changed (up to two decimal places).
- Choose how fractions of a won in the VAT are handled (default: dropped). Match the method your counterparty or accounting software uses.
- The net amount, VAT and total appear right away. [Copy results] copies the results table as text.
Example
With a net amount of 1,234,567, a 10% rate and "Drop", the VAT is 123,456.7 → 123,456 and the total is 1,358,023. The other way round, a VAT-inclusive total of 1,358,023 gives VAT of 1,358,023 × 10% ÷ 110% = 123,456.6 → 123,456 and the net amount 1,234,567 comes back. A net amount of 12,345 has VAT of 1,234.5: dropped it is 1,234, rounded half up or up it is 1,235.
How it is calculated
| Input | Calculation |
|---|---|
| Net amount | VAT = net amount × rate (fractions by the selected method), total = net amount + VAT |
| VAT-inclusive total | VAT = total × rate ÷ (100% + rate) (fractions by the selected method), net amount = total − VAT |
VAT rates and tax types can change with legislation. Check the latest National Tax Service guidance before filing or issuing a tax invoice.
Supported formats, limits and privacy
- Input: a whole amount of 0 or more (in KRW, commas allowed, up to 999,999,999,999) and a rate from 0 to 100% (up to two decimal places).
- The default rate of 10% is the general taxpayer rate in the Korean National Tax Service VAT guide (checked 2026-10-30). This tool does not decide whether a transaction is simplified-taxed, exempt, zero-rated or subject to another rate. Check with the National Tax Service or a tax professional and change the rate field yourself.
- Fractions of a won in the VAT are handled by the selected method (drop, round half up, round up), and the net amount and total are made consistent with that VAT. Tax invoices and accounting systems may use a different method, so if you are 1 won off, pick the same method.
- Net amount → VAT = net amount × rate, total = net amount + VAT. Total → VAT = total × rate ÷ (100% + rate), net amount = total − VAT. In both directions net amount + VAT = total holds exactly. All arithmetic uses integers, so there are no floating-point errors.
- This is a single-amount calculator. A tax invoice that handles fractions per line item can give a different total.
- What you enter is calculated only inside this browser. It is not sent to a server or stored, and it disappears when you close the page.
Frequently asked questions
How do I get the net amount from a VAT-inclusive amount?
The net amount is the total ÷ 1.1 and the VAT is the total minus the net amount (at 10%). For example, 11,000 gives a net amount of 10,000 and VAT of 1,000. This tool first fixes the VAT to the won and then takes net amount = total − VAT, so the two always add up to the total you entered.
Why am I 1 won off?
When the VAT has a fraction of a won, the result differs by 1 won depending on whether it is dropped, rounded half up or rounded up. For example, 10% of 12,345 is 1,234.5: dropped it is 1,234, rounded half up or up it is 1,235. If it does not match a tax invoice, try another method.
Does it handle exempt or zero-rated transactions?
Entering 0 in the rate field gives VAT of 0, but this tool does not decide which transactions are exempt or zero-rated. Check whether VAT applies and at what rate with the National Tax Service or a tax professional.