For several rooms, calculate each floor area and add the areas before estimating cartons. For rectangular rooms, area is length × width. Then apply the waste or cut allowance you choose and divide by the coverage printed on the flooring carton, rounding up to a whole carton.
Measure each room or section
Use a sketch to keep track of rooms, closets and connected spaces. Split an L-shaped room into rectangles, calculate each rectangle, and add them. Avoid counting a shared boundary twice; the calculation is for floor area, not wall perimeter.
Example: Three rectangular rooms measure 12 × 10 feet, 8 × 9 feet, and 6 × 4 feet. Their areas are 120, 72 and 24 square feet, for a combined 216 square feet.
Apply a project allowance and carton coverage
If you choose a 10% allowance for this example, the planning coverage becomes 216 × 1.10 = 237.6 square feet. If the selected carton covers 20 square feet, 237.6 ÷ 20 = 11.88, so the estimate rounds up to 12 cartons. Both the allowance and carton coverage are inputs, not universal values.
Cutting layout, room shape, plank or tile pattern, defects, offcut reuse and future repair stock can change the amount. Follow the product guidance and confirm the order with the installer or supplier. Carton coverage may be listed differently across products, so check the package for the exact item.
Keep product and layout consistent
Where possible, plan the order for the same product, finish and lot information, and check supplier return rules before purchase. If one room uses a different material, estimate it separately. For carpet, roll layout changes the cut plan, so use the Carpet Calculator for that material rather than treating roll goods as cartons. The carpet roll-width guide explains why room orientation matters.
Enter the combined area, chosen allowance and package coverage in the Flooring Calculator to estimate cartons.
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