Mattress dimensions are an important factor to think about if you want to guarantee yourself a good night's sleep. If the size of your mattress doesn't suit your body shape you'll have a hard time maintaining a comfortable position throughout the night – especially if your body is too long for the mattress, because your feet will end up dangling over the edge.
There are over a dozen official different sizes of mattress, ranging from toddler size through to a Grand King. Exact mattress dimensions differ depending on what part of the world you're in. Here we'll focus on mattress dimensions in the US and the UK.
The smallest bed sizes available are the cots designed for babies and toddlers. The dimensions of these are 27 1/4 inches by 51 5/8 inches. In centimeters this equates to 69 by 131. In the UK they're slightly longer at 55 inches (140cm).
The next size up is a mini single at 30 by 70 inches (76 by 178 centimeters).
A modern cot is the same width as a mini single (30 inches) but it's slightly longer at 74 inches. That equates to 76 by 188 centimeters.
The twin is also commonly known as a single (twin is not to be confused with double). In the US a twin is 39 by 75 inches (99 by 191 centimeters) with the UK version being slightly narrower at 36 by 75 inches (91 by 191 centimeters. These sizes are fairly uniform throughout the EU but twins are generally a bit bigger in Asia.
A double is the smallest of the mattress dimensions you'd want to consider for sleeping two adults. In the US a double is 53 by 74 inches (135 by 188 centimeters) with the UK version being narrower and longer at 48 by 75 inches (122 by 191 centimeters). In the EU a double is 55 by 75 inches and in Asia it's 48 by 78 inches.
The Queen is a fairly standard size around the world – in most cases when you buy a Queen it will be measured according to US dimensions. The standard is 60 by 80 inches (152 by 203 centimeters).
The California Queen is not a size you come across very often these days. It was popular back in the days when waterbeds were more common, but many people have moved away from these types of beds now. The California Queen is simply a slightly longer version of a Queen, 60 by 84 inches (153 by 213 centimeters).
The King size is the common choice for the bedrooms of many couples. There's a significant difference between King dimensions in the US and UK though. In the US a King is 76 by 80 inches – almost a square – which equates to 193 by 203 centimeters. So as you can see it's wider while not actually being any longer than a Queen. In the UK, a King is 60 by 78 inches (152 by 198 centimeters) which is actually much closer to the American standard for a Queen.
A California King is slightly more rectangular in shape than a standard King. It's narrower and longer, at 72 inches wide by 84 inches long. (183 by 213 centimeters). This suits tall people better than a standard King because it provides extra room to stretch your legs out.
The US and UK have different variations up from King Size. In the US it's the Grand King, and in the UK it's the Super King. A Super King is 72 by 78 inches (183 by 198 centimeters). The American Grand King is a whopping 80 by 98 inches (203 by 249 centimeters). The Grand King is not a widely available size as it's only made by certain manufacturers and only appeals to a niche market.
So another consideration in mattress dimensions is availability of bedding and sheets in the size of bed you choose. If you choose an uncommon bed size your choices may be limited. But these days even if you can't find what you are looking for at your local store you will be sure to find something you can order online.
Don't forget when considering mattress sizes that the mattress has to fit in your house. I know of people who have had a mattress delivered only to find that there was no way to get it into the bedroom. If a mattress won't fit around corners and up the stairs do you want to go through the trouble of removing windows and hoisting your mattress to get it into the bedroom? That's something to take into account before buying.
Another problem can be trying to save a few dollars and settling for a smaller size. It's worth it to wait and get the right mattress dimensions to suit you rather than you and your sleep partner to be cramped and uncomfortable for years to come.