It depends on what charger you use. Mine will fully charge in less than 2 hours (from about 5-10%) using the provided Samsung charger and USB 3.0 cable. My iPhone 5 would fully charge in about 3 hours using the 10W Apple charger. However, I do notice that it takes over 2 hours to charge my S5 when using a 10W charger with a micro-USB cable instead of the Samsung 15W charger and USB 3.0 cable. That being said, it would take forever for my iPhone 5 to charge if I relied on an older 5W Apple charger or a universal USB 2.0 5W charger.