How to tell how much GB of data I'm using?

I have 3 GB of Internet data for my iPhone 4 but how do I know how much I have used

You can check your usage on your iPhone by going to Settings --- General --- Usage. There are also other useful apps that you might want take a look at here that will have more features relating to data usage: http://m.lifehacker.com/5916276/the-best-data-usage-tracker-for-iphone

  • Why is my iPhone 5 using so much data? I just got my iPhone 5 four days ago, and I've already gone over my 200mb data plan. Before I had the iPhone, I had a Blackberry Torch 9800, and I've never gone over my data plan. I use the phone the same amount as I used my Blackberry, and I'm connected to Wi-Fi throughout 90% of the day, and rarely use data. So why am I going through my data so quickly?
  • Why is my iPhone 5 using so much data? - 1 For the last couple of months my data usage has skyrocketed! I have gone from not coming close to my 750 megabytes to having to beg EE to upgrade me to a 1gb package which I'm now on round to going over double! The only thing that has changed since I got my phone was a new 4g sim a few months ago but apart from that I havnt changed any setting.
  • When using Kik messenger on iPhone with your data plan, how much mb does it use? I'm getting an iPhone, and I tend to use kik messenger a lot on my blackberry already. How much mb of Internet does Kik use to send and/or receive messages, and picture messages? Is 500mb too low for someone who tends to use it a lot without Wi-Fi? Answers are greatly appreciated.
  • Using too much data on my iPhone 4s? I have around 100mb left on my data plan of 3GB and i have 10 days left, i turned off my cellular data will that prevent me from going over my plan?