Construction Calculator - Walls and Finishes

Carpet Calculator

Estimate carpet square footage and square yards for rooms and hallways.

Reviewed: August 26, 2026

Calculate Carpet

For the Carpet Calculator, enter length, width, waste allowance, material price, and coverage per unit. It separates measured area from allowance-adjusted order area, then reports square yards, package count, and optional material cost.

Construction measuring tools arranged beside a residential building project

Formula used

Area = length × width; order area = area × (1 + waste ÷ 100); square yards = order area ÷ 9

Carpet Calculator measurement plan showing Length feet, Width feet, Waste allowance percent

Worked carpet example

Carpet Calculator example: 21.4 ft × 9.2 ft = 196.88 ft². With 10% allowance the order area is 216.57 ft², equal to 24.06 yd².

Package rounding and usable yield

Use square feet for comparison, then ask the installer to prepare a roll-width seaming layout and quote padding separately.

Why the label value may not match the floor or wall

Carpet roll width, pattern match, nap direction, seams, stairs, closets, and irregular walls can require more material than area plus a simple percentage.

Questions specific to this calculation

How should I separate measured area from order allowance?

Enter room length and width as a first-pass area, but sketch roll direction and seams before converting the estimate into a carpet order.