Determining/Measuring the amount of data sent

I am currently doing a project that has GSM connectivity that uploads data to a server. The sim is limited in terms of data that you can use per month (10MB). I would like to know how I can measure the amount of data per transmission, or perhaps from a start point in the code to an end point. This would help me to determine if 10MB is sufficient for a month's worth of readings.

I have tried the search bar, but it has not yielded any answers/or non that I have seen.


Since you are sending the data, just count the bytes sent.