Calculate Carpet Density

Gray frieze carpet
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The density of a carpet is one of many factors that determine a carpet’s quality and overall performance. Despite a common misconception, carpet density and carpet face weight are not interchangeable terms that mean the same thing, although face weight is one factor used to calculate density.  Face weight and density are two entirely different components when it comes to evaluating the quality of a carpet.

  • Carpet face weight refers to the weight of the fiber found in 1 square yard of carpet. The standard is measured in ounces.
  • Carpet density refers to how close together the fibers are tufted into the carpet backing.

How to Calculate Carpet Density

Carpet density is calculated using the following formula:

  1. Carpet face weight multiplied by 36
  2. divided by carpet pile height
  3. equals density, measured in ounces per cubic yard

The pile height is the length of the carpet fibers from their end tips to the point where they reach the carpet backing. In the above formula, pile height should be represented as a fraction of an inch, reflected in decimal format. For example, a pile height of 1/2 an inch would be represented as 0.5, while a pile height of 1/4 an inch would be 0.25, and so on.

The number that results from the above density calculation will be a four-digit number. For example, a carpet with a 50-ounce face weight and a pile height of 1/2 an inch would have a density of 3,600 ounces per cubic yard (50 x 36 / 0.5 = 3,600).

Judging Carpet Quality

Don’t use one factor alone as an indicator of a carpet’s overall quality. All factors (density, face weight, twist, fiber type, etc.) all work together to determine how the carpet will look and perform overall. Each of these factors must all be taken into consideration when making a decision on the appropriate carpet for your home.

However, all other things being equal, the higher the carpet density, the more durable the carpet will be, and the more pleasing it will be underfoot. Just as a lawn is more luxuriant if the grasses are thick underfoot, a carpet with higher pile density will feel plusher and will hold up better with wear.

Minimum Density Values

For optimal performance in normal household conditions, a density value of 3,000 or higher is ideal. According to The Carpet and Rug Institute, Inc., extra heavy traffic conditions (such as are found in heavy commercial use) require a minimum density of 5,000.