Size Guide

How to Choose the Right Mattress Size for Your Bedroom

When it comes to mattresses, size matters. The right mattress size offers enough space for sleeping comfortably without feeling restricted or constrained.

When evaluating the various mattress dimensions available for purchase, buyers need to keep certain considerations in mind before making a selection:

  • How Many People Will Sleep on It? The number of people intending to sleep on the mattress ranks among the primary issues shoppers must consider, as couples obviously need a larger mattress size than solo sleepers.
  • Height & Weight of Sleepers Personal stature plays a major role in deciding which mattress to choose, as well. Smaller mattresses generally prove suitable for young children and teenagers, while fully grown adults typically require more expansive mattress sizes.
  • What Size Room? In addition to considering the number and size of people planning to use the mattress, shoppers must select a mattress size appropriate for the space allotted.

Fortunately, offers all the most popular mattress sizes in a variety of comfortable styles.

Small Mattress Options


The smallest mattress size available, crib mattresses perfectly accommodate newborn babies and infants.


Twin mattresses represent the next step up from the crib mattress size and make ideal selections for growing children as well as young adults residing in dormitories or other small living spaces. This bed and mattress size is common to trundle beds, bunk beds, and even day beds.

These mattresses were popular for adult sleepers in the early parts of the 20th century but, as the average size of Americans started to increase, they were replaced by the newly-popularized King and Queen size beds. In today’s world, twin-size beds are seen almost exclusively in kid’s rooms.

  • Bed Size: 44″ x 88″
  • Mattress Size: 39″ x 74″

Twin XL

The Twin XL is nearly identical to regular twin-size beds—the only difference being an extra six inches in overall length. Twin beds are the go-to choice for youth beds, including most bunk beds, but are often abandoned in late teenage years and early adulthood. College dorm rooms utilize the Twin XL for two reasons; the first being their smaller width and the second being a suitable universal length to simplify the procurement process across campus. After all, it’s much easier for colleges to manage to order 20,000 of the exact same product rather than catering to 3-4 different sizes.

  • Bed Size: 79″ x 88″
  • Mattress Size: 39″ x 80″


Another popular choice for older children and young adults, a full-size mattress is the same length as a twin mattress but offers a wider surface area.  Despite offering more space than the twin mattress size, full mattresses remain most suitable for people sleeping individually rather than as part of a couple.

  • Bed Size: 79″ x 88″
  • Mattress Size: 39″ x 80″

Big Mattress Options


Queen mattresses rank as the best mattress size for the majority of shoppers in the market for a new bed and boast enough room for couples and single sleepers alike.

  • Bed Size: 64.5″ x 86.125″
  • Mattress Size: 60″ x 80″


A king-size mattress features increased mattress measurements to serve as the largest standard option available and provides maximum sleeping space for customers with big enough bedrooms.

  • Bed Size: 79.5″ x 88.9″
  • Mattress Size: 76″ x 80″

California King

Expanded king, sometimes called California king, is available from some mattress manufacturers. Manufacturers have experimented with other sizes such as Olympic queen, but they are no longer produced.

The California King bed is an often misunderstood bed size that’s actually slightly narrower than standard king-size beds but four inches longer. This bed size first became popular on the West Coast of the United States as a custom-designed size popular among movie stars and the Hollywood Elite. After several decades of marketplace evolution the California King, Queen and King size mattresses have all become standard options in the bedding industry.

  • Bed Size: 80.5″ x 89.3″
  • Mattress Size: 72″ x 84″

Bed Size vs. Mattress Size: What’s the Difference?

Arguably the most important consideration to make when picking out a bed or mattress is to stop and make yourself aware of some basic dimensions. This may seem arbitrary—even silly—but will help throughout your entire shopping process. We’ve hammered through plenty of mattress reviews to find the best mattress in each category but all will be for naught if we can’t help ensure you order the right size for your bed! Below are some of the simplest of these ideas with a bit of elaboration to help understand why they’re so important.

Mattresses are Smaller than Bed Frames

In most cases, you’ll find that mattress dimensions are going to be less than bed frame dimensions. This means king-size bed dimensions are slightly larger than king-size mattress dimensions. This is because a mattress has to fit inside a bed frame! Notable differences are platform beds and Murphy beds.

Box Springs Raise Mattress Height

Many shoppers complain of their mattresses being either too low to the ground or too high from the ground. In most cases, this issue can be resolved through the addition or removal of box springs. Box springs are usually offered as an add-on by mattress retailers but rarely included. Box springs have a very negligible impact on overall mattress comfort so if you’ve already got a set—use those for your new mattress! Just know; a mattress you’ve tried in the store may not have the same height in your home without box springs.

Exact Bed Dimensions May Vary

Bed frames aren’t governed by as rigid of sizing guidelines as mattresses. The overall dimensions of a bed frame may vary wildly between design and manufacturer—even for the same size bed frame. That means that the king bed dimensions from one furniture brand may be entirely different than the king bed dimensions from another. Don’t stress about this—unless otherwise stated each bed frame size has been designed to accommodate that size of a mattress, regardless of that bed frame's specific dimensions.

Bed Frames Come In Adult And Kids

You aren’t likely to find this written anywhere on a retailer’s website, but bed frame designs aren’t always available as King, Queen, Twin, and Full sizes. In many cases, manufacturers design bedroom collections for either adults or kids—kids furniture is often referred to as a ‘youth collection’ by designers. Before you get your heart set on any bed design make sure it is available in a size that will accommodate the mattress you plan to use it with.

Common Questions

From time to time, we find that our readers run into the same problems. In such cases, we try to build resources to better understand specific issues. This article was one such effort, but we felt charts and explanations of bed and mattress sizes didn’t fully address common concerns. Below, you’ll find several common questions and concerns that often plague the mattress-buying process.

Can I use Twin size box springs for my King Size mattress?

No. King size mattresses can accommodate non-King size box springs in most cases but not all. Two twin mattresses are the same width as a king-size mattress but not the same length. Only two Twin XL size box springs can be used to substitute for King Size box springs.

Can I flip my Mattress Over?

Maybe. Some mattresses are designed to be flipped over and some are not. Flippable mattresses feature comfortable materials on both the top and bottom, often in varying degrees of firmness.

Layla Sleep’s two-sided memory foam mattress is a good example of one such design. You have a layer of memory foam on top designed to provide a medium-firm feel and one layer of memory foam on the bottom designed to provide a firm feel.

Most memory foam mattresses have a much denser base layer of foam on the bottom that would not be comparable to the comfort of the top layer. However, this layer would still be somewhat sleepable in our opinion, if you were in a pinch.

Other mattresses, such as traditional spring mattresses, aren’t designed to flip and often contain very uncomfortable materials on the very bottom. Sleeping on the bottom side of a one-sided mattress could damage the top side. Always check with the manufacturer.

About the Measurements

The bed and mattress measurements that were included in this article are to provide an average illustration of dimensional differences between standard sizes. It’s important to recognize the context of these numbers, and that bed sizes vary much more so than mattress sizes.

For example, each mattress we compared for this article had the exact same length/depth measurements for the available sizes. The height/thickness measurements varied considerably but, as a general rule, mattress sizes are the same regardless of brand.

On the other hand, beds and bed frame dimensions can vary wildly between different brands. Much like mattresses, bed frames are usually most different in their height, but overall width and depth/length vary considerably as well. As a general rule, look at the specified size of a bed rather than the actual dimensions to be sure that your mattress will fit. For example, never mind that a certain Queen bedframe measures an overall width of 96″—it’s still only going to accommodate a 60″ wide mattress!