A double bed

A bed is a piece of furniture mainly used for sleeping upon. They are also commonly used for relaxing, sitting, reading, and for sexual activities.

Beds come in a wide array of shapes and sizes. Early beds were little more than piles of straw or some other natural materials. An important advancement was raising them off the ground, to avoid drafts, dirt, and pests.

To make beds more comfortable the top layer is normally a mattress. Originally these were bags of straw for most people and filled with feathers for the wealthy. Eventually new fillings such as cotton and artificial fillers became common. In modern times most mattress use springs or solid foam.

At the top of the mattress, to provide greater support for the head, most people use a pillow. Also used is some form of covering blanket to provide warmth to the sleeper, often sheets, a quilt, or a duvet.

The bed frame may simply be made of wood or metal, but many also use springs. Most expensive and bulky, but also strong and comfortable are box springs, a large mattress-sized box containing wood and springs. A valance may be used to make the bed frame match the rest of the bedding.

Bed sizes

Most countries have a standard set of 4 sizes of mattress. While the "Double" size appears to be standard between English speaking countries, based on the imperial measurement of 4' 6" by 6' 3" the others sizes tend to vary. The European sizes differ again being based on metric system.

(Width by length. Metric sizes (Europe) rounded to nearest half decimetre; inch sizes (US, UK, AUS) rounded to nearest inch.)

The sizes in the UK, other than the Double, vary compared to the US sizes, being generally smaller. The US Queen corresponds to UK King and King to Super King.

The Australian Single is the same as in the UK while the Queen is the same as the US. The Australian King size differs again, having the length of the US King but the width of the UK Super King.

The European or continental basic sizes are similar to the UK but have a set length of 2 metres (width by length, Imperial sizes rounded):

These dimensions are for the mattress – the actual bed frame will be a little bigger in order to fully encompass and support the mattress. The thickness of the mattress may vary considerably.

Other less common sizes are

US:

Single Extra Long 

39" × 80" (1 m × 2.05 m)

Three Quarter 

48" × 75" (1.2 m × 1.9 m)

Olympic Queen 

66" × 80" (1.7 m × 2.05 m)

Californian Queen 

60" × 84" (1.5 m × 2.15 m)

Eastern King 

78" × 80" (2 m × 2.05 m)

Californian King 

72" × 84" (1.85 m × 2.15 m)

UK:

Small Single 

30" × 75" (0.75 m × 1.9 m)

Super Single 

41" × 75" (1.05 m × 1.9 m)

Three Quarter 

48" × 75" (1.2 m × 1.9 m)

Australia:

Extra Long Single 

36" × 80" (0.9 m × 2 m)

King Single 

41" × 80" (1.05 m × 2 m)

Three Quarter 

48" × 75" (1.2 m × 1.9 m)

Europe:

Extra Small Single 

0.75 m × 2 m (29½" × 78¾")

Small Single 

0.8 m × 2 m (31½" × 78¾")

Large Single 

1 m × 2 m (39½" × 78¾")

A king-sized bed differs from the other sizes in implementation, as it is not common to have a king-sized box spring; rather, two single-sized box springs are used under a king-sized mattress.

Types of bed

There are many varieties of bed:

• A bunk is a bed used in a confined space.
• A bunkbed is two or more beds one atop the other.
• A cot is a small bed used by babies and infants.
• A futon is a traditional style of Japanese bed.
• A hammock is a piece of suspended fabric.
• A Manjaa is traditional Punjabi bed made of tied ropes border by a wooden frame.
• A Murphy bed is a bed that can hinge into a wall or cabinent to save space.
• A pallet, a thin lightweight mattress.
• A sofabed, a bed that is stored inside a sofa.
• A trundle bed is a bed usually stored beneath a twin bed.
• A waterbed is a bed/mattress combination where the mattress is filled with water.