Calculate the floor area
For a rectangular room, multiply room length by room width.
Floor area = Length × Width
Example room
A 15-foot by 12-foot room contains 180 square feet of floor area.
15 × 12 = 180 ft²
Add a flooring waste allowance
The measured room area is rarely identical to the material quantity needed. Boards, planks or sheets must often be cut to fit edges and room features.
- Simple rectangular rooms generally produce less waste.
- Diagonal or patterned layouts can create additional offcuts.
- Irregular rooms may require more material.
- Keeping spare matching material can help with later repairs.
Adjusted area = Floor area × (1 + Waste %)
Calculate boxes of flooring
Flooring packages usually state their coverage in square feet. Divide the adjusted area by the coverage per box and round up to the next full box.
Boxes = Adjusted area ÷ Coverage per box
Measuring irregular rooms
Divide irregular spaces into smaller rectangles, calculate each area and add the results. Closets and connected areas should be included when they will receive the same flooring.
Check the product label
Actual package coverage and installation waste depend on the flooring product and layout. Use the manufacturer's stated box coverage before purchasing.