How to Measure a Mattress

Most of the time, when you buy a new mattress, you know its dimensions because they’re standard measurements. For example, a queen is always 60 by 80 inches. If it isn’t, it’s not a queen mattress.

However, there may be instances where you don’t know your mattress’s dimensions for whatever reason. Maybe it was a gift. Perhaps a spouse or parent purchased it for you. Things can get hairy if you don’t know your mattress’s dimensions, and it’s time to buy sheets or a new bed frame.

The good news is, measuring your mattress is easy. With a tape measure and a few minutes, you can determine what size bed you have.

Measuring Length and Width

To learn what size your mattress is, you need to measure its length by its width. First, strip the sheets and protector from the mattress. Your mattress should be bare before you measure it.

Next, take a tape measure and get the width of the mattress by stretching the tape from the left side to the right side across the middle of the mattress. The center will be the widest part of the mattress.

Then, measure the mattress from the head to the foot of the bed. Again, it’s best to stretch the tape across the center of the mattress. Once you have your width and your length, you should know the size of your mattress (more on that below).

Measuring Thickness

Your mattress’s depth doesn’t determine what size it is. But mattress thickness does impact how high your bed will be when you add:

To get the height of your mattress, measure from the bottom of the mattress to its highest point. If you’re measuring for fitted sheets, include your mattress topper size in this measurement, as it will go under the sheet too.

Standard Mattress Sizes and Dimensions

Once you measure your mattress’s length and width, it’s likely the mattress size will fit into one of the following sizing categories.

Twin

The twin size mattress is the smallest bed size. Twin beds are just 38 by 75 inches. That makes them perfect for kids’ and teens’ rooms, college dorm rooms, and any other smaller room. Regardless of its thickness, if your mattress measures 38 by 75 inches, you have a twin.

Twin XL

Twin XL mattresses add five inches of extra length to the twin mattress for a total of 38 by 80 inches. Twin XL beds are good for taller sleepers who still need a compact bed to fit in a smaller space.

Full

The full size mattress is 75 inches long like the twin, but it’s 54 inches wide. The full size bed is also called the double bed because it can allegedly accommodate two sleepers. However, 27 inches is not enough sleeping space to be comfortable for most people.

That makes the full or double bed better suited to individual sleepers who want more wiggle room than a twin bed has.

Queen

The queen mattress is the most versatile of the bed sizes. The queen size bed measures 60 by 80 inches. That means it’s comfortable for couples. It’s a good choice for guest rooms. It’s large enough for all but the biggest master bedrooms. And it’s small enough for childrens’ and teenagers’ rooms.

King

The standard or eastern king size mattress is the biggest bed size in terms of surface area. It’s 76 by 80 inches. As a result, the king bed offers the same space per person as a twin XL mattress.

That makes the king mattress the most comfortable choice for average-height couples.

California King

The California king size mattress is the longest standard bed size. At 72 by 84 inches, this bed is a good option for super-tall sleepers who find that even the queen and king don’t offer enough legroom. It’s also the best choice for those with longer and narrower master bedrooms.

Split King

The split king bed is the exact dimensions of a standard king mattress (76 by 80 inches). It’s just two mattresses instead of one. That means to make a split king bed, you’ll put two twin XL mattresses (38 by 80 inches apiece) in the same king bed frame.

For some partners, a split king bed is the best mattress for couples.

Dimensions of Our Mattresses

Mattress SizeZoma MattressZoma HybridZoma Start
Twin38” by 74” by 12”38” by 74” by 12”38” by 74” by 10”
Twin XL38” by 80” by 12”38” by 80” by 12”38” by 80” by 10”
Full54” by 75” by 12”54” by 75” by 12”54” by 75” by 10”
Queen60” by 80” by 12”60” by 80” by 12”60” by 80” by 10”
King76” by 80” by 12”76” by 80” by 12”76” by 80” by 10”
California King72” by 84” by 12”72” by 84” by 12”72” by 84” by 10”
Split KingTwo 38” by 80” by 12”Two 38” by 80” by 12”N/A

Other Mattress Sizes

While these are the main mattress sizes that brands carry, there are others that are less common. One example is the smallest size bed available, the crib mattress. Crib mattresses measure about 28 to 29 inches wide and 52 to 53 inches long.

At the other end of the spectrum are oversized mattresses like the Wyoming King, Alaskan King, and Texas King. All of these sizes are larger than a standard king mattress.

Bed Bases

Box springs, mattress foundations, and other bed bases generally follow the standard mattress sizes. That means once you get your mattress’s measurements to determine its size, you can just get a bed base that’s the same size.

For example, a queen mattress needs a queen box spring or a queen mattress foundation. Whether or not you need a mattress foundation like a platform bed or a box spring will depend on the mattress type you choose.

Most types of mattresses are better served by a mattress foundation, but a traditional innerspring mattress’s feel can be improved with a box spring.

Bedding Accessories

Sheets, comforters, and blankets are a little less uniform when it comes to size. For instance, a sheet set might be designed to fit both a full and a queen.

Comforters and duvets have different drape lengths. For example, a queen duvet meant to fall all the way to the floor will be longer and wider than a queen duvet meant to hang only halfway. That means you’ll need to be aware of the dimensions of the sheets and bedcovers you purchase.

Frequently Asked Questions

What if my mattress measurements don’t fit the standard bed sizes?

You probably have a non-standard mattress size if your mattress does not fit the standard dimensions listed above. Non-standard sizes include Full XL beds, California and Olympic queens, and any number of oversize king beds like Wyoming or Alaska kings.
Google your mattress’s width and length, and you should be able to find what non-standard size it is fairly easily.

How do I measure for bunk beds?

Bunk beds can come in several sizes, including twin, twin XL, and full. That means you’ll need to measure the width and length of your bunk bed frames and buy the mattress sizes that correspond to their dimensions.
You also need to consider your ceiling height for bunk beds. To prevent the sleeper in the top bunk from hitting their head on the ceiling, there should be no less than 33 inches of space between the top bunk and the ceiling. This usually means you need a ceiling that’s no less than 100 inches high.

Can twin sheets fit on a twin XL bed?

Flat sheets may or may not work with both bed sizes, but fitted sheets likely will not. A fitted sheet made for a twin will not be long enough to fit the twin XL bed. There are plenty of fitted sheets made to fit both bed sizes, but these are manufactured in such a way that they’ll be long enough to fit the twin XL and still tight on a twin.
However, if your sheet set only says “twin,” it’s safe to assume it’s too short for a twin XL.

How do I know what size bed can fit in my room?

The general rule is you need no fewer than two feet of clearance around three sides of the bed. This will give you enough space to walk around your bedroom. However, you usually need more space than this for furniture like a chest of drawers or a pair of nightstands.

That means you’ll need a few extra feet of space on at least one side of the bed. For example, you could have two feet at the left and right side of the bed while having four or five feet at the foot. Of course, the number of extra feet necessary to accommodate your furniture depends on how much you have and how big it is.

Are there standard measurements for futons and daybeds?

Typical bi-fold and tri-fold futons come in standard sizes ranging from twin to queen. Occasionally, you might find an outlier that doesn’t fit the standard size range. But most of the time, a futon will say what standard size it is. In addition, most futons will come with their own mattresses, so you likely won’t have to worry about measuring them.

Daybeds are similar to futons in the sense that they double as a sofa and are also meant to accommodate sleepers. However, daybeds don’t fold. Most of the time, they have an uncushioned wooden or metal back and arms with a twin mattress for the seat. Some daybeds may be full size as well. But this makes them more difficult to sit on like a sofa.

Bottom Line

Measuring your mattress can be as easy as 1-2-3. First, measure your mattress’s width and length to know which size it is. And measure its depth to get a sense of your bed’s final profile once you add a frame and bed base. When you know your mattress’s size, you can purchase a frame, sheets, and any other accessories with confidence.

This article is for informational purposes and should not replace advice from your doctor or other medical professional.

Andrew Russell, Wellness Writer Andrew Russell

Andrew Russell is a part-time writer and full-time sleep enthusiast. At Zoma, Andrew lends his sleep expertise and writes many of our “better sleep” guides. Outside of Zoma, Andrew puts his advice to the test, always trying new ways to get deeper, more restorative sleep. We appreciate Andrew because he doesn’t give advice that he doesn’t follow himself, so you can feel confident his solutions for better sleep really do the trick. Andrew's work has been featured on Ladders, Bright Side, and several other publications.

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