Carpet Calculator for Stairs
Accurately estimate the square footage and yardage needed for your staircase carpeting project.
Estimated Material Requirements
Net Area (Steps + Landings):
0 sq ft
Total Area (Incl. Waste):
0 sq ft
Total Square Yards:
0 sq yd
Standard Roll Width (12ft) Length:
0 linear ft
How to Calculate Carpet for Stairs
Measuring stairs for carpet is slightly more complex than measuring a flat room. You must account for the "tread" (the part you step on), the "riser" (the vertical part), and the "nosing" (the small wrap around the edge of the step).
The Basic Formula
To find the square footage for one step, use this formula:
Step Area = [Width × (Tread + Riser + 1 inch nose)] / 144
We add one inch to the tread/riser total to account for the carpet wrapping around the bullnose of the stair. Once you have the area for one step, multiply it by the total number of stairs and add any flat landings.
Important Measurement Tips
- The Waste Factor: Always add at least 10-15% for waste. Stairs require precise cutting, and patterns must often be aligned, leading to more scrap material than a standard room.
- Landing Areas: If your staircase has a turn with a platform, measure the length and width of that platform separately in feet and multiply them to get the square footage.
- Standard Roll Widths: Carpet is typically sold in 12-foot or 15-foot wide rolls. This calculator provides the square yardage, which is the industry standard for purchasing.
Example Calculation
Suppose you have a standard flight of 13 stairs. Each stair is 36 inches wide, has a 10-inch tread, and a 7-inch riser.
- Length of carpet per step: 10″ (tread) + 7″ (riser) + 1″ (nosing) = 18 inches.
- Area per step: 36″ (width) × 18″ (length) = 648 square inches.
- Convert to square feet: 648 / 144 = 4.5 sq ft per step.
- Total for 13 steps: 4.5 × 13 = 58.5 sq ft.
- With 10% waste: 58.5 + 5.85 = 64.35 sq ft.