What apps uses most data on Iphone?

Like which ones in general? I only have a little bit of data and still have a week to go but what apps use up the most data? Tumblr, twitter, safari, games, youtube, netflix, facebook, etc… And also, when your at home and have wifi, does it use your data up or does it stay the same? Thanks:)

Youtube/Netflix uses the most data. You can easily use 1 GB in one day. If you want to avoid data usage try not to watch videos.

Netflix uses the most data by far. It uses a maximum of 560 Kbps or 252 MB per hour.