Using any phone, Tablet or PC Device whilst it's connected to your EE mobile broadband go to this link -
http://add-on.ee.co.uk/status
This will tell you how much data you have used and the remaining data you have left out of your allowance until the end of your monthly refresh Date. However if you have an unlimited mobile data plan the link will not tell you how much data you've used from your Unlimited Data Allowance.
