Both are bioethanol fuels containing 9-10% ethanol by volume and 90-91% mineral gasoline, differing in their quality standard classification.

Most electronic fuel injection cars can self-adjust fuel delivery when transitioning to E10, so general users typically do not need to remap the engine control unit.

In the US and Brazil, many car owners upgrade engine control units (ECU), fuel injectors, and fuel systems so gasoline engines can run on E85, which contains up to 85% ethanol.