How to Measure a Bed for Mattress Size

Most beds in the United States take one of five standard mattress sizes: single (or twin), double (or full), queen, king or California king. Ask a sales associate which mattress will best fit a new bed, or check to see if there is a descriptive label glued to the back of the bed frame. Antique or unlabeled bed frames can be measured to determine which standard-sized mattress will be the best fit for the frame.

Bed frame, fully assembled
Metal tape measure

Instructions

- 1
  Measure the length of the side board of the bed frame. If the sides are uneven, use the shorter measurement. Subtract 1.5 to 2 inches to allow for bedding. This is the mattress length.
- 2
  Measure the distance between the wooden blocks that hold the side boards onto the headboard and footboard. If your bed frame doesn't have wooden blocks, measure the distance between the outer edges of the side boards at the head and foot of the bed. Use the shorter measurement if the widths differ. Subtract .5 to 1 inch to allow for bedding. This is the mattress width.
- 3
  Measure from the top of the slats or bed rails nearest the headboard to the spot on the headboard where you want the top of the mattress to hit. This is the total set (mattress and box spring) height.
- 4
  Determine the correct mattress based on the size of the bed frame. Mattress sizes in any category may vary by plus or minus .5 inch. A single (or twin) mattress is 38 inches wide by 75 inches long. A double (or full) is 54 inches wide by 75 inches long. A queen mattress is 60 inches wide by 80 inches long. A king mattress is 76 inches wide by 80 inches long. A California king measures 72 inches wide by 84 inches long.

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