Trouble Finding Data Utlilized Within a Month

I am using an Arduino ESP32 with cellular connection and need to know how much data I am sending over a month for a data plan.

I am sending data every 15 minutes from 6 virtual channels. After it is sent it goes into deep sleep.

How many bites are transmitted per packet I am sending?

I would be great to have a ball park number and am unsure how to find it.

Thank you in advance