Flooring
Updated Jul 5, 2026

Carpet Padding Calculator

Calculate carpet padding rolls needed for any room, including density and thickness recommendations.

How to Calculate Carpet Padding

Carpet padding extends the life of your carpet, adds comfort underfoot, reduces impact noise, and helps hide minor subfloor imperfections. It is one of the most important choices in a carpet installation because padding that is too thick, too soft, or too compressed can void the carpet warranty. Like carpet, padding comes on rolls and is sold by the square yard in the US and square meter internationally.

Square Yards Formula

Calculate padding in the same unit as your carpet. In the US, convert sq ft to sq yd by dividing by 9:

Padding (sq yd)=L×W×(1 + Waste)9

Rolls Needed Formula

Most padding rolls cover 30 sq yd (270 sq ft). Divide your padding area by roll coverage and round up:

Rolls=⌈Padding AreaRoll Coverage⌉

Density and Thickness Guide

DensityThicknessBest For
6 lb7/16 inBedrooms, light traffic
8 lb7/16 inStandard residential (most rooms)
10 lb3/8 - 7/16 inStairs, hallways, high traffic
Memory Foam7/16 - 1/2 inPremium feel, low traffic only

Padding Types

Rebond Foam
Most common, multicolor chips bonded together
Memory Foam
Premium soft feel, compresses over time
Prime Urethane
Solid virgin foam, uniform density
Rubber Slab
Long-lasting, best for stairs and commercial
Frothed Foam
Dense, flat, commercial-grade
Fiber Cushion
Synthetic jute, best for Berber and looped
Maximum Thickness Rule
Most carpet warranties cap padding at 7/16 inch (11 mm) thick. Thicker padding feels luxurious in the showroom but causes excessive carpet flex at the backing, which leads to wrinkles, premature wear at seams, and voided warranty. For Berber and looped carpet, use even thinner 3/8 inch padding.

Pet Households and Moisture Protection

Use moisture-barrier padding designed for pets - a thin film on top prevents urine and accidents from soaking into the padding and subfloor. Without a moisture barrier, pet accidents create permanent odor traps. Common brand names include Spillsafe, Healthier Choice, and STAINMASTER PetProtect. Cost is 20-40% more than standard rebond. Combine with stain-resistant solution-dyed nylon carpet for the best long-term results.

Sound Reduction Ratings

PaddingImpact (IIC)Application
Basic rebond50-55Single-family residential
Premium rebond60-65Condos, second-floor rooms
Rubber slab65-70High-rise condos, strict HOAs
Acoustic specialty70+Home theaters, studios

Installation Steps

  1. Nail tack strip 3/8 in from all walls, pointed toward wall
  2. Unroll padding perpendicular to carpet direction
  3. Trim padding to sit just inside the tack strip
  4. Staple seams every 6 inches or apply padding tape
  5. Staple perimeter every 6 inches (not onto tack strip)
  6. Check thickness is consistent before stretching carpet on top
Standard Roll Size
Carpet padding rolls are typically 6 ft (1.83 m) wide and 45 ft long, covering about 30 sq yd (270 sq ft) per roll. Order all your padding at the same time from the same lot for consistent thickness. First-generation recycled rebond varies more than premium virgin products.
Cost Estimate (US, 2026)
Standard 8 lb rebond: $0.30 - $0.60 per sq ft ($2.70 - $5.40 per sq yd). Premium memory foam: $0.75 - $1.50 per sq ft. Moisture barrier padding: $0.45 - $0.95 per sq ft. Rubber slab: $1 - $2 per sq ft. A typical 200 sq ft room: $60 - $300 in padding. Install is usually included in the carpet installation labor.

Frequently Asked Questions