What is the difference between an efficiency and one bedroom apartment?

An efficiency apartment is a smaller version of a studio apartment. As compared to a one-bedroom apartment, the efficiency apartment has a combination living, bedroom and kitchen space, though the bathroom is separated from the living space.

An efficiency apartment is much smaller in size than a one-bedroom apartment and does not have a separate bedroom. It is not uncommon for the kitchen to consist only of a mini fridge, countertop with a microwave and possibly a small stovetop. In terms of real estate terms, efficiency and studio apartments are often used interchangeably, though there is an audible difference between these homes and an actual one-bedroom.