When it comes to comfort, a few inches makes a world of difference.

Photo: Ngoc Minh Ngo; Styling: Ed Gallagher

For something as universal and timeless as sleeping, the categories for bed sizes we use today are relatively new. It took until the end of the 19th century for bed standardization to come about—which meant you could buy a mattress, bed, and bedding from different manufacturers with the confidence that all the pieces would be the same size. However, for half a century after that, your two primary options were either a twin (a.k.a. single) bed or a full (a.k.a. double) bed.

Mattress manufacturers introduced the queen and king size beds in the 1950s as a marketing tactic to “buy bigger, sleep better.” The two larger bed sizes were not only wider, but longer than the existing standards, which did align with studies that found people were getting taller and bigger over time. Along with the introduction of the “king twin” (a.k.a. twin XL), it was thought that mattress manufacturers were aiming to completely replace the existing, shorter twin and full beds. However, the demand for shorter beds remained, and as a result, we now have five standard bed sizes (twin, twin XL, full, queen, and king), some of which aren’t that different in size.

WATCH: This Super Cheap Hack Will Make Your Bed Sheets Feel Like a Million Bucks

All the size options (not to mention alternative names for some of those sizes) can create confusion for consumers, especially between two of the most common bed sizes for adults: full and queen. So what exactly is the difference?

If you look strictly at measurements, a full bed is 54 inches wide by 75 inches long, which, when split between two people, only gives each sleeper 27 inches of space—the same width as a crib. Queen beds, on the other hand, measure 60 inches wide and 80 inches long, which is more comfortable for couples and taller individuals. It may be surprising to see how close the measurements of full and queen beds are, because that little bit of extra length and width can make a big difference—both in how they fill a room and how spacious they feel when shared by two people.

Plenty of Americans in 2018 feel the same way their 1950s counterparts did: Bigger is not always better. For single adults, a full-size bed is a practical choice. Especially if you’re living in a home with smaller bedrooms. That extra 5 inches of space for navigating your bedroom can make a big difference. Additionally, everything associated with full beds is going to be cheaper than the queen equivalent: mattresses, beds, sheets, blankets, etc. However, for non-fitted bedding like comforters and quilts, it makes sense that the full/queen size is often combined. But when it comes to comfort, queen-sized beds (if not king) are the standard for both master and guest bedrooms.