How the calculation works
Tax added = net × rate ÷ 100. Tax included = gross − gross ÷ (1 + rate ÷ 100).
A worked example
At 20%, a net price of 100 becomes 120. A tax-inclusive price of 100 contains 16.67 tax and 83.33 net.
Use the result carefully
Use the column matching how your price is quoted. This tool uses the rate you enter; it does not identify a tax jurisdiction, registration threshold or applicable rate.