Carpet Calculator
Calculate exactly how much carpet and padding you need. Get accurate estimates in square yards with waste factor included.
Room Dimensions
Carpet Roll Width
12 ft is standard; 15 ft reduces seams in larger rooms
Padding
Padding extends carpet life and adds comfort underfoot
Waste Factor
10% for rectangular rooms, 15\u201320% for irregular shapes or patterns
Your Results Will Appear Here
Enter your room dimensions, choose a roll width and waste factor, then click “Calculate” to see how much carpet you need.
Top-Rated Carpet & Installation Supplies
Hand-picked products to help you get the best results on your project.
RUGPADUSA
RUGPADUSA Premium Carpet Padding, 1/2 Inch Thick, 8x10 Feet
- ✓1/2 inch thick
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Mohawk
Mohawk SmartStrand Carpet Sample, Neutral Color
- ✓Stain resistant
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Roberts
Roberts Carpet Seaming Tape, 3 Inch x 164 Feet
- ✓Heat-activated
- ✓3 inch wide
- ✓164 feet per roll
Roberts
Roberts Carpet Knee Kicker Tool, Adjustable Length
- ✓Adjustable length
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How to Use This Carpet Calculator
Step 1: Measure Your Room
Measure the length and width of your room in feet. For L-shaped rooms, break the area into rectangles and calculate each separately.
Step 2: Choose Roll Width
Select 12 ft (standard) or 15 ft (wide). Wide rolls reduce seams in larger rooms but are harder to handle during installation.
Step 3: Include Padding
Carpet padding is almost always needed. Check the box to include padding in your estimate. Quality padding extends carpet life significantly.
Step 4: Set Waste Factor
Choose 10% for simple rectangular rooms, 15% for rooms with closets or alcoves, or 20% for irregular shapes and patterned carpet.
Step 5: Get Your Results
Click Calculate to see square yards needed, padding amount, linear feet from the roll, and estimated cost range.
Understanding Carpet Measurements
Square Feet vs. Square Yards
| Room Size | Square Feet | Square Yards | With 10% Waste |
|---|---|---|---|
| 10' × 10' | 100 sq ft | ~11 sq yds | ~13 sq yds |
| 12' × 12' | 144 sq ft | 16 sq yds | ~18 sq yds |
| 12' × 15' | 180 sq ft | 20 sq yds | 22 sq yds |
| 15' × 20' | 300 sq ft | ~33 sq yds | ~37 sq yds |
Why Waste Factor Matters
Carpet waste comes from cutting to fit around obstacles, seaming between pieces, and aligning patterns. Simple rectangular rooms need about 10% extra, while complex shapes or patterned carpet can require 15–20% extra. Always round up when ordering.
Carpet Padding Types
Rebond padding (most common) is made from recycled foam and offers good support. Memory foam padding is more expensive but provides premium comfort. Fiber padding is best for radiant heated floors. Most residential carpet uses 7/16" thick, 6–8 lb density padding.
Pro Tips for Carpet Installation
Always Round Up When Ordering
Carpet is sold by the square yard and cut from a roll. You can’t return unused portions, so always round up to the nearest whole square yard. Having a little extra is much better than being short during installation.
Quality Padding Extends Carpet Life
Don’t skimp on padding to save a few dollars. Good padding absorbs impact, reduces wear on carpet fibers, and can add years to your carpet’s life. A 7/16" thick, 8 lb density pad is ideal for most residential use.
Check Carpet Direction
All carpet pieces must run in the same direction (nap direction). If pieces are installed in different directions, they’ll look like different shades under light. Mark the direction on the back before cutting.
Place Seams in Low-Traffic Areas
Seams are inevitable in rooms wider than the carpet roll, but place them away from doorways and high-traffic paths. Perpendicular to windows is best—light hitting seams at an angle makes them more visible.
Keep Extra Carpet for Repairs
Save a few square feet of carpet from the same roll for future patch repairs. Store it in a cool, dry place. If you ever get a stain or burn, a professional can seamlessly patch the damaged area with your leftover carpet.
Frequently Asked Questions
A 12×12 room is 144 square feet, or 16 square yards. With a standard 10% waste factor, you’ll need about 18 square yards of carpet plus the same amount of padding. Our calculator factors in waste and padding to give you an accurate estimate.
One square yard equals 9 square feet (3 feet × 3 feet). Carpet is typically sold by the square yard in the US. To convert square feet to square yards, divide by 9. For example, 144 sq ft ÷ 9 = 16 sq yards.
Yes, carpet padding is strongly recommended for nearly all carpet installations. It provides cushioning and comfort, extends carpet life by absorbing impact, improves insulation and sound dampening, and helps the carpet lay flat. The only exception is some commercial-grade carpets designed to be glued directly to concrete.
Standard carpet rolls are 12 feet wide. Some manufacturers offer 15-foot wide rolls. The width matters because if your room is wider than the roll, you’ll need a seam. Wider rolls can eliminate seams in larger rooms but are heavier and harder to install.
For stairs, measure the tread depth (horizontal part) plus the riser height (vertical part) for one step, then multiply by the number of stairs. A typical stair needs about 2–2.5 feet of carpet per step. For 13 stairs, that’s roughly 26–33 linear feet of carpet, plus waste for cutting.
Carpet comes off a 12-foot (sometimes 15-foot) roll, so you buy full roll-width strips: a 10×14 room still needs a 12-foot-wide piece, plus about 3 inches of trim at each end. Our calculator lays the strips whichever way uses less carpet, then makes sure you have at least 10–20% over the room area for seams and irregular shapes. Keep leftovers for future repairs.