How to Estimate for Carpet Installation

You'd think that estimating for carpet installation would be as simple as dividing the square feet of the area by nine to get the number of square yards needed. However, almost all carpet comes in rolls that are 12 feet wide by more than 100 feet long. That means the amount of carpet needed must be figured by the best way to lay it all in the same direction, with the fewest seams.

A measuring tape provides precision when estimating carpeting needs.
  1. Measure the dimensions of the areas to be covered with the same carpet. Be sure to measure into doorways to get the full dimensions.

  2. Draw a diagram on a legal pad or graph paper pad representing the areas that will be carpeted. Indicate the measurement along each perimeter on the drawing.

  3. Look at your diagram to determine which way the carpet should run to produce the fewest number of seams. A seam should not fall perpendicularly into a doorway. Ideally, a seam also should not run along high-traffic areas. If one length of carpet will not cover a room, then the adjoining piece must run in the same direction.

  4. Draw the seams on your diagram as dotted lines.

  5. Add up the running length of a 12-foot-wide roll of carpet needed to cover the area. For instance: a room that measures 14 feet by 16 feet would take two pieces of carpet 16 feet long -- a total of 32 running feet -- with a piece 10 feet wide by 16 feet long left over to use in another room. If the carpet is run in the other direction, the same room would require two pieces of carpet 14 feet long -- a total of 28 running feet. The leftover piece would be 8 feet wide by 14 feet long. If this is the only room to be carpeted, you could use one piece of carpet 14 feet long and another piece that's 7 feet long -- split lengthwise to fill up the remaining space, for a total of 21 running feet. However, this last scenario means an extra seam, which isn't optimum.

  6. Multiply your calculation of running feet by a width of 12 feet to get square feet. Divide this figure by 9 to arrive at square yards. Carpet and installation is priced by the square yard, so this is the figure to use when estimating costs.

  7. Bring the drawing you made, and your calculations, to the carpet store. If the store is providing installation labor, someone may come to your home to remeasure and recalculate the figures. However, you figures will at least give you an estimate for budgeting purposes.


  • Not all rolls of carpet have 12 feet of usable carpet width. It is best to allow for an extra inch on each side.