Add tax onto a base price, or work backward from a tax-inclusive price to see what the pre-tax amount and tax portion were.
Sales tax and GST math goes two ways: adding tax on top of a known pre-tax price, or extracting the tax that's already baked into a total you were charged. Mixing these two up is the most common tax-calculation mistake, so this tool lets you pick the direction explicitly.
When you're adding tax, your entered amount is treated as the pre-tax base. When you're removing tax, your entered amount is treated as the final total you already paid, and the calculator solves backward for what the pre-tax price and the tax portion must have been.
A common error is taking a tax-inclusive total and simply multiplying it by the tax rate to find the tax portion — that overstates the tax, because the rate applies to the base price, not the total. Dividing by (1 + rate/100) first is what gets the base price right.
Yes. VAT, GST and sales tax are all calculated the same way mathematically — a percentage applied to a base price — only the name and rate differ by country.
Add the component rates together first (for example 9% + 9% = 18%) and enter the combined rate — the calculator treats it as a single flat percentage.
Because the rate is applied to the base price, not the tax-inclusive total. The calculator correctly divides first to find the base, which gives a smaller tax figure than naively multiplying the total by the rate.