Carpet Calculator

How to Calculate Carpet

Carpet is unique among flooring materials because it is sold by the square yard (not square foot) in the US, and it comes in fixed-width rolls. Rooms wider than the roll require seams, which affect both quantity and installation strategy. Getting the calculation right means no mid-install surprises and no costly over-orders of carpet that cannot be returned after it leaves the warehouse.

Square Yards Formula

Area in square feet divided by 9 gives square yards. This is the unit most US carpet is priced in:

Linear Feet Formula

Carpet is cut from a 12 ft (or 13.2 ft) wide roll. The linear length you need is determined by how many strips of carpet are required to cover the room width:

Fiber Type Comparison

Pile Construction

Seam Placement Rules

• Direction - all carpet pile must run the same direction; seams should be parallel to the longest wall
• Traffic - never put a seam under a doorway or in the main traffic path
• Light - place seams parallel to the strongest natural light source so shadows do not highlight them
• Furniture - avoid seams under heavy furniture that pivots when moved (desks, beds)
• Stairs - never seam across a stair tread; use one continuous piece per step

Padding Requirements

Always replace padding when installing new carpet. Old padding has compressed and no longer supports the carpet properly. Standard 8 lb density rebond is the most common choice for residential rooms. Thicker is not always better - most warranties require 7/16 inch maximum thickness. Stairs and high-traffic areas need 8-10 lb density to prevent premature wear.

Traffic Rating Guide

Stretching and Install Tools

• Tack strip - nailed around perimeter 1/4 in from walls
• Knee kicker - for short runs and corners
• Power stretcher - required by warranty for proper tension on rooms over 6 ft wide
• Seam iron - heat-activated seam tape joins strips
• Carpet knife - with row cutter and trim blades