1. Measure your room
Record the length and width of the room in feet. For L-shaped or irregular rooms, choose the L-Shape option to enter both sections at once.
What is carpet square footage?
Carpet square footage is the total floor area that will be covered by carpet, measured in square feet. To calculate carpet square footage, measure the room length and width in feet and multiply them together. Carpet is commonly sold by the square yard (1 sq yd = 9 sq ft), so dividing your square footage by 9 gives the amount to order. Always add 10% for waste from seams, pattern matching, and cuts around doorways and corners.
Getting started
How to Calculate Carpet for a Room
To calculate carpet for a room, measure the length and width in feet. Multiply length × width to get square footage. For L-shaped rooms, split into two rectangles and add the areas. Add 10% for waste, then divide by 9 to convert to square yards if your carpet is priced per yard.
2. Add waste factor
Enter 10% in the waste factor field to account for seams, cuts, and pattern matching. For patterned carpet, use 15-20% waste.
3. Get area and cost estimate
View results in square feet and square yards. Enter carpet price per square foot or square yard to estimate total material cost for your flooring project.
Quick reference
Reference
1 acre = 43,560 square feet
1 square yard = 9 square feet
1 square meter = 10.764 square feet
1 square inch = 0.00064516 square feet
Core formula
Basic Formula for Area
Area is the amount of space occupied by a 2-dimensional shape. The shape could be a floor, a wall, a playground, or a field. The simplest formula for area applies to any rectangular shape:
Area = Length × Width
Measure the length and width of the space in feet. Multiply the two values to get the area in square feet. A rectangular room that is 12 feet (3.66 meters) long and 10 feet (3.05 meters) wide has an area of 120 sq ft (11.15 sq m).
Square yardage is area measured in yards, and square meters is area measured in meters. Measure in feet, find the area in square feet, then convert to the unit you need.
For an L-shape room, split the floor into 2 rectangular sections, calculate each area, and add the results. Convert all measurements to the same unit before multiplying, if your dimensions are in different units like inches and feet.
Shape formulas
Area Formulas for Different Shapes
The Carpet Calculator supports room and rectangle formulas for flooring projects. Each formula below includes a diagram with labeled dimensions.
Room Shape
Calculate carpet area for a room
Using measurements in feet: Area (ft²) = Room Length × Room Width. Measure the longest wall for length and the perpendicular wall for width. A 12×15 room has 180 sq ft of carpet area, or 20 sq yd. Door openings do not reduce floor area because carpet extends under the opening.
Rectangle Shape
Calculate carpet area for a rectangular space
Using measurements in feet: Area (ft²) = Length × Width. Use the rectangle formula for hallways, closets, or any rectangular section that needs separate carpet measurement.
Waste factor
Adding 10% Surplus for Materials
Add a 10% surplus to your calculated area to account for material waste during cutting, breakage, and pattern matching. This waste factor applies to flooring, carpet, tiling projects, and landscaping materials.
Original Area100 sq ft
+10%
Order Amount110 sq ft
Total Material = Area × 1.10
A room with 200 sq ft of floor area needs 220 sq ft of material: 200 × 1.10 = 220 sq ft. Increase the surplus to 15% (multiply by 1.15) for diagonal flooring installation patterns or complex tiling projects with many cuts. The Square Foot Calculator includes a waste factor field for this calculation.
FAQ
Frequently Asked Questions
How do I calculate carpet for a room?
Measure the room length and width in feet, then multiply them together to get square footage. Add 10% for waste from seams and cuts. A 12×15 room needs 180 sq ft of carpet, or 198 sq ft with the 10% waste factor.
How much carpet do I need for a 12×15 room?
A 12×15 room is 180 square feet. With 10% waste, order 198 square feet or about 22 square yards of carpet. Carpet is typically sold by the square yard, so divide square feet by 9.
Do I need extra carpet for waste?
Yes, always add 10% to 15% extra carpet for waste. Seams, pattern matching, and cuts around corners and doorways create unusable pieces. For patterned carpet, increase the surplus to 15-20%.
How do I convert square feet to square yards for carpet?
Divide square feet by 9 to get square yards. Carpet is commonly priced per square yard. For example, 180 sq ft ÷ 9 = 20 sq yd of carpet.
How much does carpet cost per square foot?
Carpet costs $1 to $5 per square foot for materials, depending on fiber and quality. Installation adds $0.50 to $1.50 per sq ft. Enter your price per square foot or square yard in the calculator for an instant cost estimate.
How do I calculate carpet for an L-shaped room?
Split the L-shaped room into two rectangles. Calculate the area of each rectangle and add them together. Use the L-Shape option in the calculator to enter both sections at once and get total carpet area.