An ampere hour or amp hour (symbol: A⋅h or A h; often also unofficially denoted as Ah) is a unit of electric charge, having dimensions of electric current multiplied by time, equal to the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs. The commonly seen milliampere hour (symbol: mA⋅h, mA h, or unofficially mAh) is one-thousandth of an ampere hour (3.6 coulombs).