A plug-in hybrid has two energy stores: a battery you charge at home for short electric trips, and a gas tank for everything else. To make room for the battery, the tank is often a few gallons smaller than on the regular version of the same car.
What the smaller tank means on a trip
Once the battery is used up, a plug-in drives like an ordinary hybrid, so its range on gas is the tank size times its hybrid MPG. Each vehicle's page shows the tank and, where the EPA publishes it, the electric range.
Range extenders
A few cars, like the Chevrolet Volt and the BMW i3 with range extender, ran a gas engine mostly to recharge the battery. Their tanks are small, from under 2 gallons on the i3 to around 9 gallons on the Volt, and we list them as rated.
Recent plug-in hybrids, smallest tank first:
