How to Determine the Size of a Bed

Knowing a bed's size lets you prepare for all sorts of tasks.

Determine a bed's size to purchase mattresses and identify clearance needs.Determine a bed's size to purchase mattresses and identify clearance needs.
If you're moving an especially large bed into a house with especially small rooms, it can help you identify whether or not the bed will even fit. Knowing the bed's dimensions lets you plan a room's layout without having to actually move the furniture around a hundred times. More commonly, the bed's inner dimensions can help owners choose the appropriate mattress size for their model.

Measure the overall length, width and height of the bed at the longest, widest and tallest points of the bed frame. Hook the measuring tape's metal tab against one outer edge of the frame,open the tape to the opposite outer edge and read the measurement. Position the metal tab flush against the floor and pull the measuring tape upwards when measuring height, stopping at the tallest point on the bed frame.

Measure the opening inside the bed frame to determine what size mattress you need for the bed. Measure the width at the head, middle and foot of the bed and record the smallest size found. Measure the length along the two outer edges of the bed frame -- along the sideboards -- then record the smallest number. Measure from the top of the slats or brackets to where you want the top of the mattress to fall to determine the total height needed between the box spring and mattress.

Compare the width and height of the mattress opening against common mattress sizes to determine what type of mattress you need. Twin mattresses measure 38 inches wide by 75 inches long. Full or double mattresses measure 53 by 75 inches, queen-sized mattresses measure 60 by 80 inches and king-sized mattresses measure 76 by 80 inches. "California King" mattresses, a less-common variant of standard king-sized mattresses, measure 72 by 84 inches.

Things You Will Need

  • Measuring tape


  • Older antique beds may not hold any of the standard mattress sizes. Send your measurements to a specialty mattress manufacturer to have a custom-built box spring and mattress made.

About the Author

Brad Chacos started writing professionally in 2005, specializing in electronics and technology. His work has appeared in, Gizmodo, "PC Gamer," "Maximum PC,",, "Wired,", and more. Chacos is a frequent contributor to "PCWorld," "Laptop Magazine" and the Intuit Small Business Blog.