Updated: March 16, 2026

Do you know how wide a king-size bed is? Or the length of a queen mattress? Knowing the exact measurements for each mattress size is important information to have as you begin your new mattress search.

A mattress is a long-term investment, so you owe it to yourself to find the right bed and mattress for your particular needs. Familiarize yourself with mattress dimensions (width and length) and consider how a specific mattress size will accommodate sleepers and how it will fit in a bedroom.

If you want to upgrade in size from your current mattress, make sure you have enough available space. Or if you haven’t thought about getting a larger mattress, you should consider it — even a few extra inches can make a big difference!

Remember, there is no best mattress size — it’s all about which size is best for you. Know your mattress size options before you shop. See the mattress size chart below for exact measurements.

Standard Mattress Dimensions

Raymour & Flanigan carries a wide variety of mattress sizes so you can find the perfect fit for every member of your family! To help you make the right choice, familiarize yourself with the dimensions and differences between common mattress sizes.

Crib

Standard crib mattress dimensions are 27 inches wide by 52 inches long. Crib mattresses are designed for babies and toddlers and are no more than 6 inches deep. They are made from the same types of materials as adult mattresses, like innersprings or memory foam, to help the littlest family members catch some much-needed zzz’s.

Twin

Twin mattress dimensions are 38 inches wide by 75 inches long. Twin mattresses are the perfect size for kids of all ages while leaving enough space for play. It’s easy to fit multiple twin mattresses into a room for siblings. Twin mattresses can also be a good option for bunk beds, daybeds, and guest rooms.

Twin XL

Twin XL mattress dimensions are 38 inches wide by 80 inches long, giving you an additional 5 inches of length compared to a twin mattress. This makes twin XL mattresses perfect for teens or young adults who need the extra leg room. Twin XL mattresses are also commonly used in college dorm rooms.

Full

Full size bed dimensions are 52 inches wide by 75 inches long. Also known as a double, full mattresses can be a very versatile mattress size. They’re great for kids or anyone needing to save space in a small bedroom or studio apartment.

Split Queen

A split queen mattress is actually made up of two mattresses that each have the dimensions of 30 inches wide by 80 inches long. The separate components can be beneficial for delivery if your home has tight corners, tricky staircases, or narrow doorways. When put together a split queen has the same area as a regular queen mattress.

Queen

Queen mattress dimensions are 60 inches wide by 80 inches long. Queen mattresses are the most popular mattress size and they’re perfect for accommodating two people. Queen mattresses will fit in many smaller bedrooms and still provide a comfortable amount of sleeping space for one or two individuals.

Split King

A split king mattress is made up of two Twin XL mattresses that each have the dimensions of 38 inches wide by 80 inches long. When the two mattresses are pushed together, it has the same dimensions as a king-size mattress. A split king is ideal for  couples who have different comfort preferences. The two mattresses also allow for limited motion transfer.

Split Head King

Split head king mattress dimensions are the same as a regular king mattress — 76 inches wide by 80 inches long. The difference is a split head king has an approximate 29-inch split at the top of the mattress, allowing both sides of the mattress head to elevate separately. Unlike a typical split mattress, the bottom of a split head mattress is fully connected, so you and a partner are sleeping on the same mattress. Due to the unique shape of a split head king, a special mattress protector and sheets are needed.

King

King size mattress dimensions are 76 inches wide by 80 inches long, a full 16 inches wider than a queen mattress. They’re perfect for couples who enjoy a lot of personal space or for people who often have kids or pets sleeping in their bed. King mattresses have the same amount of space as two twin XL mattresses.

Split California King

A split California king mattress is made up of two mattresses that each have the dimensions of 36 inches wide by 84 inches long. When the two mattresses are pushed together, it has the same dimensions as a standard California king mattress. The split California king is a bit narrower and longer than a standard king size mattress.

California King

California king mattress dimensions are 72 inches wide by 84 inches long. Sleepers who are over 6 feet tall will love the additional length, while everyone can appreciate the ample space to spread out. California kings are also ideal for people with pets who sleep at the foot of their bed. California king mattresses are actually 4 inches narrower than a king so they may fit better in certain bedrooms where you could use some extra walking space on either side of the bed.

How to Choose the Right Mattress Size

There are a few different factors that will go into determining which mattress size is right for you. From your sleeping needs to the size of your budget, consider the following factors before making a purchase.

Additional Mattress Size Considerations

You should also keep the following in mind as you narrow down your mattress size options:

Why Bedding Must Match Your Mattress Size

Each mattress size requires compatible bedding. From sheets to mattress protectors, you want to ensure your bedding fits snugly and stays in place overnight. It’s as simple as matching your mattress size to your bedding size. For example, if you have a queen mattress, you should use queen-size bedding. If you’re upgrading or downgrading mattress size, you’ll need to purchase new bedding.

If your mattress is taller or has a pillow top, look for deep-pocket fitted sheets. Make sure the pocket depth meets or exceeds your mattress height for a secure fit.

For comforters, duvets, and blankets, you’ll want to ensure you have proper coverage of the entire sleeping area. If you sleep with a partner, you’ll want bedding that comfortably covers both of you while you sleep.

Mattress size also influences your pillow choices. For a queen or king mattress, having two larger pillows on each side ensures proper comfort and support for all sleepers. You may also choose to include additional accent pillows on your bed if you have the space. These pillows can help define your bedroom aesthetic and will often be removed at bedtime. For larger mattresses, 4–6 decorative pillows in varying sizes can add texture and visual interest to your space.

Learn more about building an entire sleep system beyond the mattress.

Mattress Size FAQs

Do mattress sizes vary by brand?

Widths and lengths are largely standard, but slight differences (up to an inch) can happen. Check the listed mattress dimensions and your frame’s internal opening, especially with snug headboards or platform frames.

Is a full bed the same size as a double?

Yes, a full and double both measure 53 inches wide by 75 inches long.

How do I measure my room for a new mattress?

Measure wall to wall, then map the mattress footprint with painter’s tape. Keep 24–30 inches of clearance for walkways and make sure you have enough space for door swings, dresser drawers, and window access.

Which is bigger, a king or California king?

A king mattress is wider, while a California king is longer. Both are similar in terms of total area, but their shape differs slightly. Learn more about the differences between a king and California king mattress.

How can I tell if it’s time to upgrade my mattress size?

Consider moving up if you feel crowded, your feet hang off the end of the bed, you’re waking up when your partner moves, or a child or pet shares the bed. If you’re over 6 feet tall on a 75-inch bed, switching to 80–84 inches (king or queen ) usually improves comfort.