VAT · Percentage Calculator
Move between net amount, VAT and gross total, and work out percentages and changes.
About this tool
Korean VAT is 10% of the supply value. The arithmetic is simple but the direction trips people up — add VAT to a supply value of 1,000,000 won and you get 1,100,000, but taking 10% off 1,100,000 gives the wrong answer, because the VAT inside that figure is 100,000, not 110,000. This tool asks whether the amount you entered excludes or includes VAT and calculates both directions correctly.
To extract VAT from a VAT-inclusive amount you divide by 1.1 rather than subtracting 10%, and that distinction is where most errors come from. Amounts below one won can be floored or rounded, and whichever you choose, the remaining figure is adjusted by subtraction so that supply value plus VAT always equals the total exactly.
The percentage tab holds three calculations people reach for constantly: B% of A for working out a discount or a fee, A as a percentage of B for completion rates and market share, and the change from A to B as a percentage for a rise or fall. Everything is calculated in your browser, so the amounts never leave the page.