Installed this in my S4 and it was immediately recognized by the phone. I performed a format from the phone just to see what it would do, but it didn't give me any further storage capacity with the card. With card overhead it still adds nearly 59.5GB of storage capacity to my bloated S4.I tested moving existing applications, pictures, music, and other files back and forth between my phone and the card, absolutely no problems. If you're not going to put a lot of music, pictures or applications on your phone, you'll probably be fine with no additional storage. However, if you're going to add any storage capacity to your phone, why not maximize it with a 64GB card for about $50?