Mattress size guide 2025: what's the difference between US, UK and EU sizes?

It might come as a surprise but mattress sizes are different depending on which country you're in. Whether you're shopping in the UK, US and EU, you need to take care when you're buying the best mattress online, because you could easily buy the wrong one.

A king-sized mattress in the US won't be the same size as a king-sized mattress in the UK, and not realising this fact could be a costly mistake. In T3's mattress size guide, we've set out the most common mattress sizes in the US, the UK and the EU to ensure that everything's the right size for your bedroom, and so your accessories fit suitably, too.

Bear in mind, however, there's a fair bit of inconsistency across the mattress industry, so you should always check the measurements of a mattress rather than going solely on the listed size, because these can vary between companies. Keep reading for the most common sizes in the US, UK and EU, and tips on how to find the perfect mattress size for your requirements.

How to choose the right size of mattress

The first thing to consider is the bed frame. If you already have that, it’s just a case of measuring its length and width to make sure your mattress will fit. However, if you’re ordering both bed and mattress together, you’ll have more leeway to find the right size of mattress for your specific needs.

The general rule of thumb is your mattress should be at least 10cm (4 inches) longer than the tallest person who’s going to be using it. Any less, and you’re going to end up flailing off the end of the bed and getting cold feet on a winter’s night.

Shopping for a single bed? Put your hands behind your head and measure the distance between your elbows. The width of your mattress should ideally be a little bit wider than that. The one exception is if you have problems snoring; then you might want a narrower mattress to discourage you from sleeping on your back and encourage side sleeping instead.

If you're a couple then things get more complicated. What’s important is how you and your partner actually sleep in practice: how much you move around, whether one of you starfishes, and so on. If you tend to disturb each other a lot, it may be worth investing in a large size mattress and bed, to give each of you a better chance of quality sleep.

You also need to be able to fit your bed and mattress into your room. So it’s important you measure the space you have available carefully before purchasing, although if you buy the best bed in a box mattress, you might be able to get the box through the door before you unfurl the mattress.

That said, even if you can fit a super king into your room, and can afford it, ask yourself whether you actually want to. Perhaps you’d prefer more floor space instead?

Finally, check whether there will be any obstacles to getting the bed and mattress into the room, particularly if you have narrow or windy stairs. Otherwise, you might end up with a large bed cluttering up your living room for weeks, and all the added cost and hassle of having to return it.

UK mattress sizes

Although the UK hasn’t completely abandoned imperial measures – we still drink pints and drive for miles, for instance – many of our goods are now measured using the metric system, and mattresses are no exception.

Below, we list all the main mattress sizes in the UK and their dimensions in centimetres, and in brackets you’ll find a conversion into feet and inches. But do be aware that these conversions are rounded up and not exact. So if space in your room is very tight, we’d still urge you to make your calculations using the metric side of your tape measure.

Finally, a note on the UK Queen size. Usually, a Queen is the same as a Small Double. However, that's not always the case. Sometimes it's the same as a Super King (with US sizing, a Queen size is always bigger than a Double). When shopping for a Queen, it should be fairly clear by how the models are prices, but we'd urge you to double-check the actual dimensions too.

• UK Small Single mattress: 75 x 190cm (2’6″ x 6’3″)
• UK Single mattress: 90 x 190cm (3' x 6'3") 
• UK Small Double (sometimes called Queen) mattress: 120 x 190cm (4' x 6'3") 
• UK Double mattress: 135 x 190cm (4'6" x 6'3") 
• UK King mattress: 150 x 200cm (5' x 6'6") 
• UK Super King mattress (occasionally also called Queen): 180 x 200cm (6' x 6'6") 
• UK Large Emperor mattress: 213 x 213cm (84” x 84”) 
• UK Caesar mattress: 245 x 220cm (96” x 87”)

EU mattress sizes

The countries of the European Union (which no longer include the UK), use the metric system for everything, mattresses included. If you're in the UK or USA, you're most likely to encounter EU mattress sizes when shopping at IKEA.

Below, we list all the main mattress sizes in the UK and their dimensions in centimetres, and in brackets you’ll find a conversion into feet and inches. But as with the UK list above, be aware that these conversions are rounded up and not exact. So if you need to make accurate measurements, always use the dimensions given in centimetres. 

• EU Single mattress: 90 x 200cm (3' x 6'6") 
• EU Small Double: 120 x 200cm (4’ x 6’6”) 
• EU Double mattress: 140 x 200cm (4'7" x 6'6") 
• EU King mattress: 160 x 200cm (5'3" x 6'6") 
• EU Grand King mattress: 180 x 200cm (5'11" x 6'6")

US mattress sizes

American citizens still use old English measures to measure their mattress sizes. Below, we list all the main mattress sizes in the USA and their dimensions in inches, and in brackets you’ll find a conversion into centimetres. 

These conversions are rounded up and not exact, though. So if you want to make accurate measurements to calculate the size of mattress you need, do stick to the measurements in inches.

Finally, for those unfamiliar with American mattress sizes: no, we haven't made a mistake. The terms 'Twin' and 'Single' are used interchangeably, however illogical that might sound.

• US Twin / Single mattress: 39” x 75” (99 x 191cm) 
• US Twin XL mattress: 39” x 80” (99 x 203cm) 
• US Full / Double mattress: 54” x 75” (137 x 191cm) 
• US Queen mattress: 60” x 80” (152 x 203cm) 
• US Super Queen mattress: 66” x 80” (166 x 203cm) 
• US King mattress: 76” x 80” (193 x 203cm) 
• US Cal King mattress: 72” x 84” (183 x 213cm) 
• US Super or Texas King mattress: 80” x 98” (293 x 249cm)

What are the standard duvet sizes?

The standard sizes for duvets basically follow the size of the mattress. That doesn't mean they're the same size as the mattress, though: they need to be a little bigger in order to cover you adequately. That said, if you're a couple who tends to "fight" over the duvet in your sleep, you might be better off with the next size up.

Below you'll find the standard dimensions of different sized duvets in the UK, EU and USA. (Again, though, be aware that there is a lot of inconsistency across the industry on the application of these measurements.) For more comprehensive advice, check out our duvet size guide.

Standard duvet sizes: UK

• Standard single: 135cm x 200cm (53" x 79")
• Double: 200cm x 200cm (79" x 79")
• King Size: 225cm x 220cm (89" x 87")
• Super King: 260cm x 220cm (102" x 87")
• Emperor: 290cm x 235cm (114" x 92")

Standard duvet sizes: EU

• Single: 160 x 210cm (62" x 82")
• Double: 200 x 200cm (79" x 79")
• King: 240 x 220cm (94" x 87")
• Super King: 260 x 220cm (102" x 87")

Standard duvet sizes: US

• Twin / Single: 59'' x 79'' (50 x 201cm)
• Full/Double: 80'' x 80'' (201 x 201cm)
• Queen: 90'' x 88'' (229 x 224cm)
• King Size: 90'' x 102'' (229 x 259)
• Cal King: 94" x 104" (239 x 264)

What are the standard pillow sizes?

If you thought all pillows were the same size, you'd be very wrong. Pillow sizes varying hugely from company to company, and region to region. There are, however, some generally agreed standard sizes for pillows which are listed below. As ever, though, always check before buying that the brand is question actually conforms to these measurements, as application of them is fairly inconsistent.

For buying advice, here's our full and comprehensive pillow size guide.

Standard pillow sizes: UK

• Standard / Oxford : 50 x 75cm (20" x 30")
• Standard Continental / Square: 65 x 65cm (26" x 26")
• Large Continental: 80 x 80cm (32" x 32") 
• Single Bolster: 90 x 50cm (35" x 20")
• Double Bolster: 137 x 50cm (54" x 20")
• King Size Bolster: 150 x 50cm (59" x 20")
• Super King Bolster: 180 x 50cm (71" x 20")

Standard pillow sizes: EU

• Standard: 65 × 65cm (26" × 26") 
• Continental: 80 × 80cm (31" × 31")

Standard pillow sizes: US

• Standard: 20  × 26" (51 × 66cm) 
• Jumbo: 20  × 28" (51 × 71cm) 
• Queen: 20  × 30" (51 × 76cm) 
• King: 20 × 36" (51 × 91cm)