Does the iPhone 5s use cellular data when connected to Wi-Fi?

I just got a 5s with iOS 7.1.1, and have Verizon 4G LTE. I only have 10GB of data and want to save it. My question is, if I'm connected to Wi-Fi, and go use the internet, will my phone use data anyway?

Not if you know what you're doing.

No mobile phone uses cellular data when on Wi-Fi, that is after all the whole point of Wi-Fi being free, mostly. If your not sure, turn off your cellular data while near your Wi-Fi source, Cheers.

No, it will also show at the top if its Wi-Fi or not. Otherwise if you really want to be safe, turn off cellular when on Wi-Fi (just tell Siri "cellular settings" and it will take you there).