This is how big the batteries are in the new iPhone 5S and 5C

Apple said that the battery had increased in both of the new iPhones, iPhone 5S and 5C, but maybe you wonder how big the battery really is? Well the iPhone 5S only has a 1570mAh battery. That is kinda tiny if you compare the battery to for example Sony Xperia Z1 ’ s battery that is 3000mAh. But you can’t really compare them like that, the iPhone and iOS doesn’t use as much power as Android does, and iOS is highly optimized for the hardware.
AnandTech have extrapolated the battery capacity of both the iPhone 5s and iPhone 5c from their respective FCC listings, using a simple formula. So we now have a pretty accurate info on the exact size of the batteries: a 1570mAh battery for the iPhone 5s and 1508mAh for the iPhone 5c. Compared with the iPhone 5’s 1440mAh unit, that gives us an increase of 9% in the case of the iPhone 5s, and a more frugal 4.7%, as far as the iPhone 5c is concerned
Via Phone Arena