King size bed guide

The length is the upgrade nobody mentions

A king is sold on width, and for a lot of buyers the length matters more.

A double is 190 centimetres. A king is 200. The usual guidance is a mattress at least 10 to 15 centimetres longer than the tallest person using it, which puts a double's ceiling at roughly 5'11" and a king's at roughly 6'3".

If either of you is tall, that ten centimetres is the reason to move, and it is available without going to super king width. It also matters on frames with a footboard, where feet cannot overhang at all.

75 centimetres each

A king gives each person 75 centimetres, against 67.5 in a double. That is 7.5 extra centimetres each, which sounds trivial and is an 11 per cent increase in personal width.

It is also the point at which dual firmness starts working properly. Every dual firmness mattress has a transition zone down the middle, and at king width you are both comfortably clear of it, where at double width you are not.

And at 75 centimetres each, two single duvets become a genuinely practical option, which solves more shared-bed complaints than any mattress technology.

Spring counts are quoted in king

Useful to know when you are comparing: a quoted spring count is for a king size. A double has fewer and a single fewer still, because the density stays roughly constant while the area shrinks.

So buying a king means the headline number is the number you actually get, which makes comparison between brands more straightforward at this size than at any other.

For most people, 1,000 to 2,500 in a king is the useful range. Above about 2,000 the springs get smaller and the wire thinner, which buys contouring and motion isolation at the cost of individual spring strength.

Before you commit: access and floor space

A king mattress is heavy and does not bend. A pocket sprung king can be 45 to 60 kilograms, and forcing one round a tight stair turn can damage the spring unit permanently.

Measure the route: doorways, stair width, the turn at the landing, and any low ceiling on the stairs. Boxed mattresses solve this, and traditional sprung mattresses do not.

Zip and link is the answer where access is the problem. Two singles that join, each at 90 by 200, which come up the stairs separately and give you a king at the top. They also let each person choose their own firmness.

For floor space, allow 60 to 75 centimetres each side to walk and make the bed. A king in a room that cannot take it is worse than a double in a room that can.

A US king is not a UK king

A US king is roughly 193 by 203cm, which is closer to a UK super king at 180 by 200 than to a UK king.

A US queen at roughly 152 by 203cm is the closest US size to a UK king. There is no UK queen size, so a UK listing offering one is using an imported name, and the dimensions need checking in centimetres.

European and US sizes with the same names are different

This is where most sizing mistakes come from, and it catches people buying from IKEA and from imported ranges.

Every row differs, and the length differs as well as the width on singles and doubles. A European double is ten centimetres longer than a UK one, which is the part people miss.

A US queen is roughly 152 by 203cm, closest to a UK king. There is no UK queen size, so a listing offering one is using an imported name.

Depth is the measurement nobody checks

Bed sizes describe length and width. Depth is not standardised at all, and it is what decides whether your sheets fit.

Standard UK fitted sheets are cut for about 25 centimetres. Modern hybrids run 28 to 35, and a topper adds 5 to 10 on top of that.

Add the mattress depth to the topper depth and buy a few centimetres over, because the fabric has to fold under rather than merely reach the edge.

Measure the base, not the old mattress

An old mattress has compressed and may have distorted, so measuring it gives you the wrong number.

Measure the internal dimensions of the bed frame, at the longest and widest points, and check the depth the frame will take.

Manufacturers vary by a centimetre or two even within standard sizes, which matters most on frames with a headboard and footboard where the mattress has to drop between them rather than sit proud.

Related reading

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