How can I work out tax on a invoice?

Hello all i am trying to work out how to work out tax on my invoice i have built

I have a sub total box, a shipping box, a tax box and a total. I currently have the following to work it out, but it doesn’t want to work out the tax: E26+E27+E28

  • E26 is the sub total box
  • E27 is the shipping button
  • E28 is the tax box

At the moment when i put 20% in E28, I get the sub total .20 in the amount due.

You are summing the percentage tax, not the tax amount.

Total =(E26+E27)*(1+E28)

Great thanks very much