VAT calculator
Add tax to a net price, or pull the tax out of a price that includes it.
Input
Korean VAT is 10%. Change it for another country's rate.
Result
Figures are rounded to whole units, with the tax taken as the difference so that net plus tax always equals the total.
Total
110,00010%
- Before tax
- 100,000tax excluded
- Tax
- 10,000
- Total
- 110,000tax included
The usual mistake
- A tax-inclusive 110 contains 10 of tax, not 11. Taking 10% off the total is the wrong operation — divide by 1.1 instead.
- A shortcut: with a 10% rate, the tax inside a total is the total ÷ 11, and the net is the total ÷ 1.1.
- Simplified-taxpayer schemes and zero-rated goods (books, staple foods, medical care in Korea) do not follow this arithmetic.
- Invoices are issued in whole units, so the two parts have to add back up to the total.
Tax inside common totals
| Total | Before tax | Tax |
|---|---|---|
| 1,100 | 1,000 | 100 |
| 5,500 | 5,000 | 500 |
| 11,000 | 10,000 | 1,000 |
| 33,000 | 30,000 | 3,000 |
| 55,000 | 50,000 | 5,000 |
| 110,000 | 100,000 | 10,000 |
| 550,000 | 500,000 | 50,000 |
| 1,100,000 | 1,000,000 | 100,000 |
| 11,000,000 | 10,000,000 | 1,000,000 |
How to use
- Choose the direction: adding tax to a net price, or removing it from a total.
- Enter the amount and all three figures appear together.
- The rate defaults to 10%; change it for another jurisdiction.
Frequently asked questions
How much tax is inside a tax-inclusive 110?
Ten, not eleven. The total is already 1.1 times the net, so divide by 1.1 to get the net of 100 and take the difference. At a 10% rate the tax is simply the total ÷ 11.
Why can I not just subtract 10%?
Because the 10% was charged on the smaller net figure, not on the total. Taking 10% off 110 gives 99, which is wrong by one won on every hundred.
Does this work for other rates?
Yes — the rate is an input. The same arithmetic applies at 20%, 5% or any other rate; only the divisor changes.
Why do the rounded figures still add up?
The tax is taken as the difference between the rounded total and the rounded net. Rounding each independently can leave the sum off by one unit, which an invoice will not accept.
About the VAT calculator
Quoting, invoicing and reclaiming input tax all need the same three numbers read from different ends, which is why both directions sit side by side here rather than one being buried.
The recurring error is subtracting the rate from a tax-inclusive price. The tax was charged on the net figure, so recovering it means dividing rather than subtracting.
When agreeing a price, establish whether it is quoted with tax included. An unstated assumption here is a common source of billing disputes.