Guide
King Size Bed vs Double vs Super King: Sizes Compared
A king size bed vs double: the king is 15 cm wider and 10 cm longer, at 150 x 200 cm against 135 x 190 cm. A super king adds another 30 cm of width at 180 x 200 cm, so each of two sleepers gets 90 cm instead of 75 cm.
King size bed vs double vs super king: the numbers
The table uses UK standard mattress sizes. The frame sizes are outside measurements taken from the models sold on this site. Prices are for the frame only, without a mattress.
| Double | King size | Super king | |
|---|---|---|---|
| Mattress | 135 x 190 cm (4ft 6in x 6ft 3in) | 150 x 200 cm (5ft x 6ft 6in) | 180 x 200 cm (6ft x 6ft 6in) |
| Typical frame, outside | 147 x 205 cm | 155 to 165 cm wide, 210 to 220 cm long | 189 to 192 cm wide, 218 cm long or more |
| Width per sleeper | 67.5 cm | 75 cm | 90 cm |
| Minimum room | 2.6 x 2.9 m | 2.8 x 3.0 m | 3.1 x 3.0 m (3.4 m wide keeps both walkways) |
| Bedding size | Double | King | Super king |
| Frame price on this site | Not sold here | £309 to £785 | £659 to £839 |
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The frame figures come from real models. A Cheslyn upholstered frame is 164 x 207 cm in king. Every product page lists the outside size of its frame. The full chart is on the king size bed dimensions page.
How much bigger is a king size bed than a double?
A king size bed is 15 cm wider and 10 cm longer than a double. For two people, that is 7.5 cm more width each. In area, a double mattress covers 2.57 square metres and a king covers 3.0 square metres. That is 17 percent more sleeping surface.
Measure the room for the frame, not for the mattress: the outside size of each frame is listed on its product page.
Length matters as much as width. A double mattress is 190 cm long. A person of 1.85 m has 5 cm to spare before the pillow is counted. A king is 200 cm long and gives 15 cm.
King size bed vs super king: 30 cm decides it
A super king is the same length as a king and 30 cm wider. Each sleeper gets 90 cm instead of 75 cm. A super king mattress covers 3.6 square metres, 20 percent more than a king.
The 30 cm comes out of your walkways. A king in a 3.1 m wide room leaves about 75 cm on each side of a 160 cm frame. A super king in the same room leaves about 60 cm on each side of a 190 cm frame. Below 3.1 m, one side of a super king touches the wall.
On this site a super king costs more than the same model in king. The Callum wrought iron frame is £759 in king and £839 in super king. Super king bedding also costs more than king bedding; the difference is to be confirmed by retailer.
Which size fits your situation?
- Two adults, a normal master bedroom. King size. Each of you gets 75 cm, the width of a single bed. The room needs to be at least 2.8 m wide.
- Two adults plus a child or a dog in the bed. Super king, if the room is 3.4 m wide or more. If the room is narrower, a king with 75 cm each is the practical choice.
- Anyone over 1.85 m tall. King or super king. Both are 200 cm long. A double at 190 cm is too short for comfort.
- A room under 3 m wide. King size, from 2.8 m, with one 60 cm walkway. A super king needs 3.1 m at the minimum. Below 2.8 m, a double is the only size that leaves a walkway. Check your own room on the will a king size bed fit my room page.
- One adult. A double is enough. A king gives a single sleeper 150 cm to spread out, if the room allows it.
Moving from a double to a king: what you buy again
A king size bed vs double swap replaces more than the frame. This is the list.
| Item | Do you need a new one? | Why |
|---|---|---|
| Bed frame | Yes | A double frame holds a 135 x 190 cm mattress. A king mattress is 15 cm wider. |
| Mattress | Yes | A double mattress leaves a 15 cm gap in a king frame. Typical UK king mattress prices run from £250 to £900, to be confirmed. |
| Fitted sheet | Yes | A double fitted sheet will not stretch over a 150 x 200 cm mattress. |
| Duvet and cover | Yes | A double duvet hangs short on both sides of a king mattress. |
| Pillows | No | Standard UK pillows fit all three sizes. Two pillows fill a king headboard. |
| Bedside tables | Check | Each table needs 45 to 50 cm beside a frame that is already 15 cm wider. |
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The frame is the cheapest part of the change. A king size bed frame on this site costs £309 to £785. The mattress is usually the biggest single item.
Where to look next
Every frame in the king size beds collection is listed with its outside measurements, its maximum mattress depth and its weight rating. Several models are also made in 180 x 200 cm and appear in the super king beds collection at £50 to £80 more.