VAT & GST calculator

How the calculation works

There are two directions, and mixing them up is the usual source of a wrong figure on an invoice.

Adding tax starts from a net price. Multiply it by the rate to get the tax, then add the two together. A net 1,000 at 15% gives 150 in tax and a gross of 1,150.

Removing tax starts from a gross price that already includes it. Divide by 1 plus the rate — so 1,150 divided by 1.15 returns the net 1,000. Subtracting 15% from 1,150 would give 977.50, which is wrong by 22.50.

On the rate presets

The presets cover standard rates and are a convenience, not a source of truth. Most countries also run reduced or zero rates for particular goods and services, and standard rates change with budgets. Confirm the rate that applies to what you are selling with your own tax authority or accountant, and use the custom option for anything the list does not cover.

United States: there is no VAT or GST, and no national sales tax rate. Sales tax is set by each state and often by the county or city on top of that, so the combined rate depends on where the sale takes place — and in some states there is no sales tax at all. Selecting the US option opens the rate field so you can enter the combined rate that applies to you. The arithmetic is the same as VAT once you have that number.

This is a calculator, not tax advice.

Common questions

How do I remove VAT from a total?

Divide the gross amount by 1 plus the rate as a decimal. At 20%, divide by 1.2; at 15%, divide by 1.15. The result is the net figure, and the difference between the two is the tax. Subtracting 20% from a gross amount is the common mistake — it gives a smaller number than the correct answer, because the 20% was calculated on the net figure, not the gross one.

What is the difference between VAT and GST?

Very little, mechanically. Both are consumption taxes charged as a percentage of the sale price and collected at each stage of the supply chain. The name differs by country: the UK, Ireland and most of Europe call it VAT, while New Zealand, Australia, Singapore, India and Canada call it GST. The arithmetic on this page is identical either way.

Why do the net and tax figures not always add up neatly?

Each figure is rounded to two decimal places for display. This calculator derives the tax as the difference between the gross and the rounded net, so the three numbers on screen always reconcile exactly rather than being out by a cent.