Eachnight may earn commissions for products you purchase through our links. Our articles and reviews include affiliate links and advertisements, including amerisleep advertising. Learn more Updated November 3, 2021Along with your bed’s firmness, support, and conforming qualities, the right size mattress can significantly improve your sleep. Many people choose a smaller mattress than what they need and end up feeling too uncomfortable to sleep.With so many bed sizes available, how do you know which fits your sleep style best?This article discusses different mattress sizes (standard and non-standard) and the recommended room sizes for each bed size. We will also explore how to choose the right mattress size.Mattress Sizes and Dimensions GuideMattressDimensions (Inches)Dimensions (CM)Crib27.25 inches by 51 inches69.2 cm by 129.5 cmSmall Single30 inches by 75 inches76.2 cm by 190.5 cmTwin38 inches by 75 inches96.5 cm by 190.5 cmTwin XL38 inches by 80 inches96.5 cm by 203.5 cmFull54 inches by 75 inches134.5 cm by 190.5 cmFull XL54 inches by 80 inches137 cm by 203.5 cmQueen60 inches by 80 inches152.5 cm by 203.5 cmOlympic Queen66 inches by 80 inches167.5 cm by 203.5 cmKing76 inches by 80 inches193 cm by 203.5 cmCalifornia King72 inches by 84 inches183 cm by 213.5 cmShop By Mattress Size Shop Twin Shop Twin XL Shop Full Shop Queen Shop King Shop Cal King Crib Mattress Dimensions: 28 inches by 52 inchesRoom size requirements: 7 feet by 10 feetThe crib mattress only fits inside a crib and is regulated by the federal government for safety reasons.This size mattress is usually firm and no thicker than 6 inches. To sleep comfortably on a crib mattress, a child must be shorter than 3 feet. If the child is taller than 3 feet, consider buying a small single mattress.Small Single Mattress: 30 inches by 75 inchesRoom size requirements: 7 feet by 10 feetThe small single mattress is excellent for toddler beds. The small single mattress is a standard mattress size, so most toddler bed frames will support it.Twin Mattress Dimensions: 38 inches by 75 inchesRoom size requirements: 7 feet by 10 feetThe twin-size mattress is 38 inches by 75 inches—8 inches wider than a crib bed. The twin bed accommodates children and smaller teens but isn’t long enough for a full-grown adult. An adult’s feet will hang over the edge, making it harder to get a good night’s sleep.Twin mattresses are compatible with bunk beds and conserve space for those living in a small apartment or sharing a room.Twin mattresses are easy to move because they are lightweight and small enough to maneuver in narrow hallways.Twin XL Mattress Dimensions: 38 inches by 80 inchesRoom size requirements: 9.6 feet by 10.6 feetThe twin XL size mattress is 5 inches longer than the twin bed, making it best for taller people.The twin XL mattress is a popular mattress size for college dorm rooms and pairs well with bunk beds. Twin XL mattresses aren’t as expensive as full or queen size beds, so keeping one handy for a guest is an affordable alternative.Full Mattress Dimensions: 54 inches by 75 inchesRoom size requirements: 9.6 feet by 10.6 feetA full size mattress, or double bed, doesn’t provide enough space for a couple but is a notable upgrade for a single sleeper. A double bed offers enough space to spread out but doesn’t take up much floor space, making it a good option for teenagers or young adults.Double mattresses aren’t as expensive as queen mattresses, but they are a bit harder to move because they aren’t as compact and lightweight as a twin XL.Full XL Mattress Dimensions: 54 inches by 80 inchesRoom size requirements: 9.6 feet by 10.6 feetA full XL mattress has an extra 5 inches of legroom, accommodating the height of a full-grown adult. We don’t suggest this size for couples because the width is too narrow; however, this bed makes an excellent guest room bed—especially if you don’t have the budget for a queen.Queen Mattress Dimensions: 60 inches by 80 inchesRoom size requirements: 10 feet by 10 feetQueen mattresses offer enough room for couples to sleep comfortably. We suggest this mattress size to couples who don’t need much space or a single adult who needs extra room.The queen size bed is an excellent option for a guest or master bedroom. Many people get queen mattresses for their older teenagers and turn it into a guest bed when the child moves out.Queen size beds come as split queens (two separate mattresses). These work well for couples with different firmness preferences.Olympic Queen Mattress Dimensions: 66 inches by 80 inchesRoom size requirements: 10 feet by 10 feetThe Olympic queen offers 6 additional inches of width for couples who don’t need a king-size bed but want extra room. This mattress isn’t a standard size bed, so it isn’t as accessible in mattress stores. Olympic queen size bedding is also challenging to find.You can use Olympic queen mattresses in RVs, campers, and mobile homes.King Mattress Dimensions: 76 inches by 80 inchesRoom size requirements: 12 feet by 12 feetKing mattresses measure 16 inches wider than queen beds, and they’re long enough for most adult sleepers. The king-size bed is the widest mattress of the standard bed sizes, so it provides enough room for two people to have their own space.King mattresses are available as a split option, which is two twin XL beds side-by-side. This option allows couples to have different mattress preferences instead of compromising on a single bed. Many people choose the split king mattress size because it works well with adjustable beds.California King Mattress Dimensions: 72 inches by 84 inchesRoom size requirements: 12 feet by 12 feetCalifornia king mattresses are 4 inches narrower and 4 inches longer than a king mattress. The extra length can accommodate extra tall people. This mattress can comfortably fit two adult sleepers and parents who co-sleep with a child.The California king bed comes in a split option, so each sleeper can select a different mattress firmness from their partner.How to Choose the Best Mattress SizeYou want a bed big enough to encourage restful sleep, so you will need to consider who sleeps in the bed, how much space they need, and your bedroom’s size.Who Sleeps In the Bed?If you’re buying for yourself, you most likely know what mattress size suits you best; however, if you have a sleeping partner or children you co-sleep with, you have to think about their sleep preferences as well.For adults and couples, the queen mattress is probably the smallest size you’d want to sleep on. Full XL beds don’t offer enough room for a couple to sleep comfortably. If you and your partner need extra sprawling room, a king bed provides more space.A single sleeper who needs extra spreading room would fit comfortably on a full XL—otherwise, a single sleeper will probably sleep well on a twin XL.Refer to our guide below to find the best mattress size for your circumstances.Toddlers, children, or young teenagers are comfortable on these mattress sizes:Small SingleTwinTwin XLFullSingle adults, college student, or older teenagers are comfortable on these mattress sizes:Twin XLFull XLQueenTwo adult sleepers are comfortable on these mattress sizes:QueenKingCalifornia KingTwo adult sleepers who co-sleep with children are comfortable on these mattress sizes:KingCalifornia kingYour Body TypeYour height may affect the bed size you need to sleep comfortably. For people 5 feet 5 inches or taller, we suggest a mattress at least 80 inches long to prevent the feet from dangling over the bed’s edge and disrupting sleep.Room SizeBefore you buy a bed, consider the bedroom the mattress will occupy. A larger mattress needs more space than a small bed. You need to leave enough room for movement between the mattress, the walls, and any furniture.Overcrowding the bedroom can make your sleep environment stressful, which can make it hard to fall asleep. So, make sure to measure your room before deciding on a mattress size.Room size requirements for mattress sizes:Mattress SizeRoom Size (Inches)Room Size (CM)Crib7 feet by 10 feet213.36 cm by 304.8 cmSmall Single7 feet by 10 feet213.36 cm by 304.8 cmTwin7 feet by 10 feet213.36 cm by 304.8 cmTwin XL9.6 feet by 10.6 feet292.60 cm by 323.08 cmFull9.6 feet by 10.6 feet292.60 cm by 323.08 cmFull XL9.6 feet by 10.6 feet292.60 cm by 323.08 cmQueen10 feet by 10 feet304.8 cm by 304.8 cmOlympic Queen10 feet by 10 feet304.8 cm by 304.8 cmKing12 feet by 12 feet365.76 cm by 365.76 cmCalifornia King12 feet by 12 feet365.76 cm by 365.76 cmYour Sleep PositionYour preferred sleep position can give you an idea of how large a sleep surface you need. If you toss and turn a lot or sleep spread-eagle, you’ll need more room than someone who uses a small portion of the bed.Those who need more legroom and restless sleepers should choose a larger mattress; on the other hand, couples who like to snuggle or those who don’t take much space can sleep comfortably on a smaller bed.Consider Your HomeMattresses are heavy and can get damaged when you’re moving them from place to place. If you plan on buying a large bed, such as a king or California king, you might want to wait until you’re settled in your forever home—or a place you are going to live in for at least 10 years.Consider how you’re going to move your mattress. If you’re purchasing a larger mattress, your home might not accommodate it. Measure doorways and halls so ensure you’ll have enough room to maneuver it.You might consider getting a bed in a box mattress, which is shipped to your doorstep in a small box—this way, you can easily move the mattress to your bedroom.BudgetLarger mattresses contain more materials and, therefore, cost more. If you want a bigger bed, you will need a larger budget. Twin mattresses commonly cost between $300 and $600, and a quality queen size mattress can cost between $700 and $2000.You’ll have to consider the material quality and type of mattress you want to buy, too:Purchasing a low-quality mattress might save your wallet initially, but you’ll have to replace it more frequently than higher-quality beds, costing you more money in the long run.Some mattress types, like all-latex and hybrid mattresses, cost more than others.Frequently Asked QuestionsWhat’s the most popular mattress size?The most popular mattress size is the queen, which measures 60 inches wide and 80 inches long. It’s the most popular mattress size amongst both single adults and couples because it fits in most bedrooms, fits two people comfortably, and works for taller people. It’s not as expensive as a king or California king mattress, but still offers more room than a full mattress.What is the best size bed for a couple?The best mattress for a couple depends on the couple. Sleeping partners who like to cuddle will enjoy a queen mattress far more than a king. On the other hand, a couple who needs more spreading room will receive better sleep on a king mattress than a queen size.How is mattress size measured?In the United States, the mattress’s width and length are measured in inches. Other countries have different sizes that are measured in centimeters. If you’re interested in measuring your own mattress, lay a tape measure from top to bottom and across its middle.What is the size of a single mattress?A single mattress is another name for a standard twin mattress, which makes it 38 inches wide and 75 inches long. Originally, a single referred to one mattress while a twin was used for a mattress that was part of a pair. However, this nuance has been lost and the terms are now used interchangeably.What’s the difference between a twin and single mattress?Despite the different names, single and twin mattresses are the same size, both being 38 inches wide and 75 inches long. The name difference started because twin beds were originally sold in a pair, thus the term “twin.” Eventually, brands started selling twin mattresses separately and started calling them “single” mattresses.The term “single” stuck around for a while, but brands started calling single beds “twins” once again, despite there only being one bed of the same size. Nowadays, calling a 38 by 75 inch mattress a “single” is more common in Europe and the UK, while the term “twin” is commonly used in the US and Canada.ConclusionNo matter how much room you or your sleep partner needs, there is a mattress large enough to help you sleep comfortably. If you choose a mattress size too small for you or your sleep partner’s sleep style and height, your sleep quality could suffer.About the author Rosie Osmun CERTIFIED SLEEP COACH Rosie Osmun is a Certified Sleep Science Coach. She received her Bachelor of Arts in Political Science and Government from Arizona State University College of Liberal Arts and Sciences.For more than 13 years, she has been involved in the beauty, health, sleep, and wellness industries. Her work has been featured and published in Byrdie, Lifehacker, Men’s Journal, EatingWell, and Medical Daily. 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