How to Measure a Room for Carpet
Measuring for carpet requires more care than measuring for hard flooring because carpet comes in fixed-width rolls. Here's the proper method.
What You'll Need
- Tape measure (25 ft minimum)
- Notepad and pencil
- Calculator (or use the Carpet Calculator)
Step 1: Measure Length and Width
Measure the longest dimension of the room (this will be the direction the carpet runs). Then measure the perpendicular dimension. Record both in feet and inches, then convert to decimal feet (e.g., 12 ft 6 in = 12.5 ft).
Step 2: Identify the Roll Width
Ask your carpet supplier what roll width is available. Standard residential rolls are 12 ft wide. Some premium lines come in 13.5 ft, and commercial rolls are 15 ft. The roll width determines how many strips you need.
Step 3: Determine Carpet Direction
Carpet should run along the longer dimension of the room to minimize seams. If your room is 15 × 14 ft, the carpet runs along the 15 ft direction, and strips are cut across the 14 ft dimension.
Step 4: Calculate Strips
Divide the cross-dimension by the roll width, rounding up:
Strips = ceil(cross dimension ÷ roll width)
For a 14 ft cross-dimension with a 12 ft roll: ceil(14 ÷ 12) = 2 strips.
Step 5: Calculate Carpet Length
Each strip runs the full length of the room:
Carpet length = strips × room length
2 strips × 15 ft = 30 linear ft of carpet.
Step 6: Convert to Square Yards
Carpet is priced by the square yard. Convert:
Square yards = (carpet length × roll width) ÷ 9
(30 × 12) ÷ 9 = 40 sq yd.
Step 7: Add Waste
Add 10% for cuts and seaming (15% for patterned carpet):
40 × 1.10 = 44 sq yd to order.
Use the Carpet Calculator
The Carpet Calculator handles all of these steps automatically — just enter room dimensions and roll width. For irregular rooms (L-shaped, angled walls), divide into rectangles and calculate each separately.