You can definitely look at how many Mb were used on your device on a previous bill. Please log in to My Verizon on www.verizonwireless.com. On the right side of the screen please select view bill then select the month you would like to view the usage from. After selecting the month please choose charges by line select the Mobile Broadband number and you will be able to see Mb used. I use this all the time. Another great tool we offer is Account Analysis located on My Verizon as well this auto calculates and checks to make sure your on the right plan for you.