Question: what is the difference between a single mattress and a twin mattress?
Answer: Single and twin are two terms for the same bed size. There is no difference between the two, and both terms are often used interchangeably. “Single” used to be the more popular terminology, but today, “twin” is more commonly used. ... The twin bed size is generally 38 inches by 75 inches (sometimes 39 inches by 75 inches).