I sell in online to the rest of the European Union, based in the UK.

This is how EU sales tax works.

Only businesses who volunteer or who have an annual turnover over $124,000 have to charge sales tax.

All UK customers are charged sales tax at the UK rate of 20%.
UK businesses registered for sales tax can claim the sales tax back from the government. So they effectively do not pay sales tax.

All other EU customers are charged sales tax at the UK rate of 20%.
EXCEPT if they are a business registered for sales tax in their own country, then they do not pay.
Even if they are charged they can claim the sales tax back from their own government.

Anybody outside the EU is not charged sales tax.


Different EU countries have different rates of sales taxes and corporation taxes.
So if you are a private individual then you can buy something from another country at a cheaper rate. But you pay more in shipping charges, so it isn't any cheaper.

If you purchase something from outside the EU then your government may still charge you sales tax on the value of goods imported.
There are a few UK companies that starting selling from the channel islands to avoid charging customers sales tax, which they may still be liable for as above.


Different EU countries have different rates of corporation (business profit) taxes, which is why many USA companies have their European headquarters in Ireland or Luxemborg.