Beyond the waste percentage included in our calculator, it’s generally wise to purchase an additional 5% extra carpet as a safety margin. This extra material serves several important purposes: it provides insurance against measurement errors, allows for future repairs if a section becomes damaged, and accounts for unexpected installation challenges. For patterned carpets or complex room layouts, this extra margin becomes even more important. Some homeowners also choose to keep larger remnants for creating matching area rugs or runners. While this means a slightly higher initial investment, it can save significant time, money, and stress if you ever need to match your carpet in the future.

For most residential installations, closets should be included in your room measurements rather than calculated separately. Measure the closet’s depth and width, and add this area to your room’s square footage. However, there are exceptions to this rule: walk-in closets are typically large enough to warrant separate measurement, especially if they have unique shapes or dimensions. Additionally, if you’re planning to use different carpet in closets than in the main room, you should calculate them separately. When working with a professional installer, they’ll typically include standard closets in their room measurements, but always clarify this point when obtaining quotes to ensure accurate estimates.

Stairs require special calculation methods that differ from standard rooms. For a standard straight staircase, measure the width of the stairs, then the depth of the tread (the horizontal part you step on) and the height of the riser (the vertical part). Add the tread depth and riser height, then multiply by the stair width and the number of steps. For landings, calculate as you would a small room. Stairs typically require 15-20% waste allowance due to their complexity and the need for precise cutting and installation. For winding staircases or those with special features, it’s best to have a professional measurement done, as these can be particularly challenging to calculate accurately. In our calculator, you can enter stairs as a separate “room” with appropriate dimensions and a higher waste percentage.

Carpet can be measured and priced in either square feet or square yards, which sometimes causes confusion. One square yard equals 9 square feet (since a yard is 3 feet in each direction, and 3×3=9). To convert between these measurements: multiply square feet by 0.111 to get square yards, or multiply square yards by 9 to get square feet. Historically, carpet was often sold by the square yard, but many retailers now price by square foot. Always confirm which unit is being used when comparing prices. Our calculator works in square feet (or square meters), but can be easily converted. If a retailer quotes $27 per square yard, that’s equivalent to $3 per square foot ($27 ÷ 9 = $3). Being aware of these measurement differences helps ensure you’re making accurate price comparisons.

Carpet tiles (sometimes called carpet squares) offer an alternative to traditional rolled carpet that can be advantageous in certain situations. Consider carpet tiles for: high-traffic areas where individual tiles can be replaced if damaged; DIY installations, as they’re easier to handle without professional equipment; spaces where access to the subfloor might be needed periodically; areas with unusual shapes or obstacles that make traditional carpet installation challenging; and temporary installations or rental properties where future changes are likely. Carpet tiles typically generate less waste (often 5% or less compared to 10-20% for rolled carpet) and don’t require seaming in the traditional sense. They’re calculated simply by measuring the total square footage and adding a small waste factor for cuts along walls and obstacles.