How to use this calculator
Choose whether the entered price includes tax. Enter a rate applicable to your transaction and quantity.
Formula and method
Inclusive = exclusive×(1+rate). Exclusive = inclusive/(1+rate). Tax = inclusive−exclusive.
Worked example
At an illustrative 10% rate, 100 exclusive becomes 110 inclusive; 110 inclusive contains 10 tax.
Assumptions and supported scope
Arithmetic only. Does not determine whether a sale is taxable, the applicable rate, exemptions, VAT credits, invoice rules or legal obligations.
Method references
Method and worked example checked against the calculator implementation. About our methods · Report a correction