Check the VAT rate – it’s preset to 20 percentage
Enter the amount – Net amount or Gross amount
Click "Remove VAT" or "Add VAT" to calculate VAT amount.
The standard rate of VAT in the UK was increased from 17.5% to 20% on 4 January 2011.
The reduced rate of 5% is applied to some goods and services such as children’s car seats and home energy.
Zero VAT rate is applied to a range of products and services to do with health, publishing and kids’ clothing.
If you want to add VAT to the price, you just need to divide the price by 100 and then multiply by (100 + VAT percentage). That's all, you got the price including VAT (Gross value).
If you want to subtract VAT from the price, you need to divide the price by (100 + VAT percentage) and then multiply by 100. Now you know the price exclusive VAT (Net amount).