Why is my VAT calculation incorrect in the UK?

[yixo]

Shopify is calculating the rate of VAT incorrectly. It should be 20% but is coming out lower at around 17%
How can i fix this so i can show the correct amount of VAT to customers on their invoices?

Im only set up to collect VAT in the UK, the business and customer addresses are uk based.

[yixo]

[Rostislav]

HI Yixo,

The calculation is correct. Note that all prices are shown VAT inclusive . you total order is 78.47 GBP including 20 percent VAT

So VAT is to be calculated as : 78.47/120*20=13.08