At home, we have about 5GBs of Internet. I'm the most techy savy, so whenever the Internet runs out everyone gives me a hard time like I'm the only one who uses it, which pisses me off. Admittedly, I do use the Internet the most time wise, but I am the only one who really has a clue about the amount of data things require, and how much I directly download (as far as files are concerned).

We have a modem / router connected to a wireless router. I used to check the amount of data sent and received using the wireless router, but now the router gets shut down at night and the measurements get refreshed. Even then, we have a MySky box (which is sorta like Tivo for New Zealand / Australia, and there is a different version of it in the UK I believe) which connects to the Internet ever so often and uses data too, including downloading movies, and updating its software, among other things. But this directly connects to the Internet, and doesn't go through either of the routers so I am unaware of its usage. Aside from that, my mother goes on websites often caked with high res images, and my father is regularly downloading apps for his iPhone and browsing trading sites, and other Internet sites. So when my father gets a text alert that we have 20% of our data left, everyone gets shitty with me and becomes defensive. One day, we checked the data use on our providers website and we had used over 100mb of data in one day, yet I hadn't been online at all (well, I went on in the afternoon to DV and check my email, but that wouldn't exceed a few hundred KB let alone a few hundred MB, not to mention I cache almost everything).

What I want to know is if there is a program for Mac OS that can keep track of bytes sent and received to and from my computer, so I can keep tabs on how much data I am using and have some nice hard evidence to prove it. Also, I can limit myself to so many MBs a day if I do find I am choking the Internet supply. Is there a program available for such a use?