Carpet Installation Cost Guide: Calculate Carpet & Padding

Measuring for Carpet

Carpet is measured and sold by the square yard (not square foot). To convert: divide square feet by 9. Measure each room's length and width in feet, add them together, divide by 9 for square yards, then add 10% waste for seams, cuts, and pattern matching.

Example — 12×15 foot bedroom: 12 × 15 = 180 sq ft ÷ 9 = 20 square yards. Add 10% waste = 22 square yards of carpet to order.

Important: carpet comes in standard widths of 12 or 13.5 feet. For a room wider than 12 feet, you'll need a seam. Seams add waste and labor cost. Plan your layout to minimize seams and place them in low-traffic areas, not in doorways or the center of the room.

Carpet Padding: The Foundation of Comfort

Padding is installed under carpet and significantly affects comfort, noise reduction, and how long the carpet lasts. Thicker and denser padding is better — but there's a limit. Too-thick padding under loop-style carpet (like berber) causes premature wear.

6-lb density, 7/16 inch thick: Builder-grade padding. Adequate but not luxurious. Low cost.
8-lb density, 1/2 inch: Standard residential upgrade. Good balance of comfort and durability.
10-lb density, 7/16 inch: Premium for cut-pile carpet. Dense and durable under heavy traffic.
Berber/loop carpet: Use thin, firm padding (3/8 inch max) to prevent premature stretching and wear.

Carpet Types and Cost Ranges

Cut pile (textured/plush): Soft, comfortable, hides footprints. $2–$6/sqft. Most popular residential choice.
Berber (loop pile): Durable, resists staining, less soft underfoot. $2–$8/sqft. Good for high-traffic areas.
Frieze (twist pile): Very durable, informal look, hides vacuum tracks well. $3–$7/sqft.
Pattern/cut-loop combination: Decorative, formal appearance. $4–$10/sqft.
Nylon: Most durable fiber, best stain resistance, best for families with pets and kids. Premium price.
Polyester: Soft, good color retention, less durable than nylon. Budget-friendly.

Installation Costs

Professional carpet installation typically costs $0.50–$1.50 per sq ft for labor, not including padding or removal of old carpet. Here's a complete cost breakdown for a 200 sq ft bedroom:

Carpet material (mid-grade, $4/sqft): $800
Padding (8 lb, $0.75/sqft): $150
Installation labor ($1/sqft): $200
Remove old carpet ($1/sqft): $200
Total: ~$1,350 ($6.75/sqft all-in)

Stairs and Special Areas

Stairs are priced differently — typically $3–$5 per stair for installation. A standard staircase of 13–14 stairs costs $40–$70 in installation labor. Stair carpet requires more cuts and is more labor-intensive than room carpet. Waterfall installation (carpet folds over each step) is easier and cheaper; Hollywood (wrapped tightly around each step nose) looks more elegant but costs more.

Frequently Asked Questions

How much carpet do I need for a 12×15 room?

A 12×15 room = 180 sq ft ÷ 9 = 20 square yards. With 10% waste, order 22 square yards. If the room is an irregular shape or has closets, measure each section separately, add all areas, convert to square yards, and add 10%. Most carpet retailers quote prices per square yard, so always convert from square feet.

What carpet is best for high-traffic areas?

For high-traffic areas like hallways, stairs, and family rooms, choose nylon fiber with a tight, dense pile — berber, frieze, or textured cut pile. Nylon is the most durable fiber and resists crushing and staining better than polyester or olefin. A higher face weight (32+ oz) indicates denser, more durable carpet. Pair with a dense, low-profile padding (8–10 lb).

Do I need to replace carpet padding?

Yes, always replace padding when installing new carpet. Reusing old padding is false economy — it's compressed, may harbor allergens and odors, and won't support the new carpet properly. New padding costs $0.50–$1.50/sqft and is essential for the new carpet to feel and perform as designed. Some installers will include padding in their package price.

How long does carpet installation take?

A professional crew can install carpet in a typical 3-bedroom home (500–700 sq ft of carpet) in 4–8 hours. Larger jobs or homes with many transitions, stairs, and custom cuts take longer. The slowest part is usually removing old carpet and padding, hauling it away, and prepping the subfloor. Plan for a full day for any whole-home carpet replacement.

How often should carpet be replaced?

Quality carpet in a typical household lasts 10–15 years. Carpet in high-traffic areas or homes with pets may need replacement in 7–10 years. Signs it's time: matting and crushing that doesn't recover after cleaning, permanent stains, persistent odors despite cleaning, visible tears or fraying. Regular vacuuming (2×/week) and professional cleaning every 12–18 months significantly extends carpet life.