Not big, not clever - but 100% free. The VAT calculator is designed to take some of the monotony out of working with VAT. The app is simple in it's design. The first tab is designed to calculate the standard current VAT rate in the UK. Enter your amount and tap the relevant button to be shown the amount that is VAT and the total including or excluding VAT as appropriate. The second tab does the same, but for the reduced VAT rate of 5% that applies to many fuel bills and some hygiene products.