A single bed is suitable for an individual. This is ideal for bachelors or guest rooms or or kids' room or if you have a servant room.
The dimensions for a typical single bed are 36" X 75".
Twin beds are nothing but single beds that are narrower and can fit into tiniest bedrooms. They are good choices for kids' room or guest room and often come as bunk beds or have 'trundle' fitted under them that can be pulled out to accommodate a sleepover friends. They are 39" wide and about 75" long. Their bedsheets are easily available but it may be too short for some adults.
Extra long twin beds are 39" wide like a twin bed but is 80" in length to accommodate tall teenagers and adults and are favorite choices for college dorm rooms or attic rooms for singles. However, finding bedding for it can be bit of a headache.
It is not necessary that 'standard' beds and bedding sizes is same everywhere so it is advisable to have the exact measurements with you for better fittings.
Double Bed or Full Bed
A double bed measures 54" X 75". So it is just one and a half times larger than a single bed. If you and/or your family members have a large body frame this is not the right choice for you.
Double and full sized beds may be too short for some adults.
Queen Size bed
This measures around 60" X 78" and is larger than the double/full bed. This allows allow each person 30" of space, which is still much less than the one offered by the twin bed. However, couples often prefer to use it because it occupies less floor area and fit snugly into small master bedrooms of new couples or guest rooms.
Olympic Queen Size bed
An 'Olympic queen' bed is slightly bigger than the standard queen size but neither queen-sized not king-sized bedding will not fit it correctly.
King Size bed
Standard King bed or Eastern King bed is 76" wide and 80" long and allows for 38" of space per person for a couple, while California or Western King bed is 72" wide and 84" long, allowing 36" of width per person and more vertical space for taller persons.
You can also opt for two extra-long twin beds instead on one standard sized king bed to allow greater versatility.
You may need to search for right fit of sheets before buying one.