Using a Bandwidth Monitor?

Most devices (hotspots, phones) have a bandwidth monitor built in. Here's a pic of my hotspot showing data usage.

 

I use the "my data manager" app for my android phone. It allowes me to block monitoring for wifi so it only calculates the actual data in the main graph. It does shpws wifi usahe on another screen. Ot allows me to set the date my plan cycles and I have it set to turn off mobile data when I reach a certain usage level. This keeps me from going over my data limit. It usually shows slightly higher usage than verizon shows on their web sight and app. Which I am fine with as it will keep.me from going over.

 

I use my samsung s3 on verizon network as a hotspot from time to time. It has an option to turn off the data at a certain interval. I would suggest you find a device similar.