Technically, according to specifications for the power adapter of iPad it supplies
5 Voltsalong with current up-to
2.1 Amps (12W). In the other hand, we have iPhone original power adapter that supplies
5 Voltswhile unlikely pushes
1 Amp (5W)at max which is less current than the later.
Can I Safely use iPad Charger for iPhone?Yes, it is completely safe to charge any iPhone with iPad Power Supply, that's your answer in advance just before we go explaining further. Apparently, it's not only safe to use but even more interestingly you can charge your iPhone FASTER than usual using the iPad power adapter instead.
Why it is SafeThat being said, when it comes to electronics it's known that devices draw current from the power supply on demand, meaning it doesn't matter if Amperes are higher than minimum requirement as long as the power adapter rated at the same voltage value which is in our case
5 Voltsfor both iPad and iPhone.
Charge iPhone FasterThe reason for why it's actually more efficient to charge your iPhone using the iPad adapter is that it can supply double the amount of current than the original iPhone adapter, and since devices draw current on demand that makes iPhone able to draw from
2.1 Amps (12W)available, the iPhone will be able to charge noticeably faster than being limited to
1 Amp (5W)of current only.