Does data used on Wi-Fi count toward my monthly data limit?

I currently am on a 500mb/month data plan through SFR (French company) on an iPhone 3.In order to keep track of myself I continually check the "Cellular usage" section of my phone's settings. In three days I'm up to 80 mB which at first scared me because at that rate I will surely go over my limit, but I know that 80% of my phone use is when I'm connected to Wi-Fi, either at school or at home. Are the numbers my iPhone is showing me what I have used outside of Wi-Fi, or does that include it? I just need to know whether or not to worry.

If you're using Wi-Fi it won't count towards your limit

Wi-Fi is always free data