Built in Calculator
Use Xero’s built-in calculator
So you quoted your customer a percentage-off discount, and you want to make sure you got the price right? No worries, Xero has a built-in calculator.
In the quantity, unit price and discount fields, you can actually add a basic multiplication sum and Xero will figure out the right answer for you.
Just insert a plus sign (+) between two numbers to add (so for example 495.12+56.89), a minus (-) to subtract, a star (*) to multiply or a backslash to divide.
Xero will do all the maths for you.