I sell to customers in the US or Australia; can I use the same calculator for sales tax or GST?
Yes, for the arithmetic. Any tax charged as a single percentage of the pre-tax amount works in add and extract mode, whatever it is called. For example, 80 with 8.875 entered as the rate gives 7.10 of tax and a total of 87.10. Whether you have to collect that tax at all is a question the calculator cannot answer.
Why the same calculator works
VAT, sales tax and GST differ a great deal in their rules: who collects them, when, and on which goods. But on a single invoice the calculation is usually the same shape: a percentage of the pre-tax price added on top. That is exactly what the VAT calculator does; it neither knows nor needs the tax's name.
Two worked examples
- Add: an item at 80 before tax, with 8.875 entered as the rate. Tax 7.10, total 87.10.
- Extract: a tax-inclusive price of 110, with 10 entered as the rate. Net 100, tax 10.
The rate field accepts decimals, so 8.875 goes in as it is, and the calculator repeats it in the Rate you entered line so you can spot a typing slip.
When more than one rate stacks
In some places one sale carries, say, a state rate and a city rate. If every rate is charged on the same pre-tax amount, add them into one figure and enter that. Two rates of 4 and 4.875 on the same base equal 8.875 entered once, and the result matches working each separately and adding them up.
If one tax is charged on an amount that already includes another, adding the rates is wrong. Work it in two stages instead: add the first, then take that total and add the second. Confirm how the taxes stack with the relevant authority; the tool does not know.
What the calculator cannot tell you
- Whether you must collect sales tax from a customer in another country at all.
- Which rate is correct for the customer's city or state.
- Whether the marketplace you sell on collects the tax on your behalf.
Those are legal and tax questions that vary by place and change over time. Start from official sources in the customer's country or a qualified adviser. If you are pricing a product for sale abroad, work out your pre-tax price first in the Selling-price calculator, then add the rate you have confirmed.
Common questions
Is 8.875 a real rate somewhere?
In this article it is an arithmetic example only. Always confirm the official rate yourself.
Does choosing USD in the currency list change anything?
Not the calculation; the result is just shown with the currency code.