What is the difference between a US and UK king size mattress?

A couple sleep in a bed wearing eye masks
(Image credit: Getty Images)

In the UK, you walk on the pavement, in the US, it's a sidewalk. You'll throw your mattress packaging in the garbage in the US, and in the rubbish in the UK. And if you're buying a mattress, the king you order in the US might turn out to be a super king in the UK – wait, what?

US king size and UK king size are different mattress sizes with the same name, and the US king is longer and wider than the UK king. To make matters even more complex, the UK king is closer in size to the US queen (which is different again from the seldom-seen UK queen size). Confusing, right? We've put together this guide to help you understand exactly what's going on when you order one of the best king size mattresses.

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Is US king size the same as UK king size?

US and UK king size refer to two different mattress sizes, which can be a little confusing if you're shopping for a new bed. The US king size is wider and longer than the UK king size (76in x 80in compared to 60in x 79in). The UK king size is actually closer to the US queen size, while the UK super king is closer to the US king.

Confused? It's a tricky one to navigate, so let's break it down:

  • US king size: 76 inches wide x 80 inches long (193cm x 303cm)
  • UK king size: 60 inches wide x 79 inches long (150cm x 200cm)
  • US queen size: 60 inches wide x 80 inches long (152cm x 203cm)
  • UK super king: 71 inches wide x 79 inches long (180cm x 200cm)

US sizes tend to be a bit larger than their closest UK equivalent, and the difference between a US king and a UK king is significant. If you're ordering a bed from an international brand, make sure to check the actual dimensions – don't just pick a size based on name, or you might find your mattress is hanging off the frame. For more information, check out our UK vs US mattress size guide.

A couple share a bed together

(Image credit: Getty Images)

King size mattresses are among the bigger sizes in both the US and UK sizing range. So, who should buy a king size mattress? They're great for couples, particularly those who like their own space in bed (and don't want to consider a sleep divorce). 

They're also good for families with kids who sometimes like to snuggle up with their parents. Although, if you're in the UK, you might prefer to go for the super king, while US families should be comfortable enough with the king (sorry, it got confusing again).

If you're not sure what size you want, make sure to look for a bed with a good mattress trial. A mattress trial is a risk free period to test the bed and decide whether it works for you. This also gives you an opportunity to see if the size is right (and send it back if it isn't).

Ruth Jones
Staff Writer

Ruth is TechRadar’s Sleep Writer. She’s here to help you find the perfect sleep setup for your budget and personal preferences. As well as keeping a keen eye on everything that’s going on in the world of mattresses, she regularly speaks to experts to help you learn how to improve your sleep habits, whether that’s by debunking sleep myths or explaining the science behind it all. Prior to joining the TechRadar team, she wrote features and product guides for new parents hoping to get a decent night's sleep, as well as writing for a variety of online spaces.