I have put 23% vat to my sales invoice but it's not calculating 23% it's a different amount , why?

Hi there, info2400. The reason your 23% VAT amount isn't calculating as expected is that the Price is inclusive of sales tax option was selected when the item was created.

When this is enabled, QuickBooks assumes the price you entered is the final total you want to charge. To keep this from changing, the system pulls the tax out from within that price instead of adding it as an extra charge on top.

To fix this, please check your item setup by going to the Gear icon > Products and services > select the item and click Edit > go to the Sales section > untick Price is inclusive of sales tax > and click Save. 

If you need further help, don't hesitate to get back to us.