Differences between efficiency and studio apartments include layout, size and design of the kitchen and the presence of the optional loft. Landlords sometimes use the two terms interchangeably, so these differences are not always relevant when discussing apartment options, and sources disagree as to the defining characteristics of each.
Both efficiency and studio apartments have small spaces and do not have separate bedrooms, but efficiency apartments tend to be smaller than studios, though not always. Studios can be very large while preserving the same simple design as smaller studios.
The kitchen in an efficiency apartment is often larger, with larger appliances than in a studio apartment, and is often separated by a wall or partition from the rest of the room. Many studios lack this partition, and each may only have a kitchenette with half freezers. Because of inconsistencies in terminology, some landlords or writers consider full kitchens to belong to studios, and kitchenettes to efficiency apartments, and some units that lack kitchens or kitchenettes still go by the name "efficiency apartment."
Some studios come with a loft option, which is hardly ever the case with efficiency apartments. The loft usually consists of a raised, partially open platform within the studio that is accessible by stairs.