The $7,500 federal tax credit can apply to plug-in hybrid vehicles too, but there are specific criteria. For plug-in hybrids, a critical factor is battery capacity; generally, the battery must be at least 4 kWh to qualify for the credit. The credit amount can differ and often scales with battery size, so it may not always match the full $7,500 that fully electric vehicles can receive. Be sure to check the IRS guidelines or consult a tax professional for the latest requirements and to ensure eligibility.