There are a couple ways to measure a cup and handle, but most books/sites will measure the bottom to the cup to the right side of the cup, or depth of the cup.

So, in the case of the GBP/AUD (after posting a rounded bottom last month) here is a chart that will show you a projection of what we could possibly target:

Disclaimer: I am long the GBP/AUD from last week on the breakout