How to Estimate Flooring for a Room

Most flooring mistakes come from measuring, not math. Here is a reliable way to get the quantity right the first time.

By the Mirovi Home editorial team · Updated September 2026

Step 1: sketch and measure

Draw a rough floor plan. Measure each room at its longest and widest points, wall to wall, in feet and inches, and convert inches to decimal feet (6 inches = 0.5 ft). Include closets, hallways and any area under appliances that will be floored.

Step 2: split odd shapes into rectangles

An L-shaped room is two rectangles. Calculate each and add them. For a bay or angled wall, measure the rectangle that encloses it — the extra becomes part of your waste.

Example: a 15 × 13 ft living room (195 sq ft) plus a 4 × 9 ft entry (36 sq ft) is 231 sq ft.

Step 3: add a waste allowance

Every row ends with a cut, and some pieces will be damaged or have defects. A common allowance for a straight lay in a simple room is around 10%; diagonal, herringbone and chevron patterns, or rooms with many corners and doorways, need more. Your product’s installation instructions may give a specific figure.

Step 4: convert to boxes

Flooring is sold by the box; the square footage per box is printed on the carton and product page. Always round up:

Step 5: don’t forget the extras

• Underlayment — rolls are sold by area; use the room area plus a little overlap.
• Transitions and trim — measure doorways and the room perimeter for baseboard or quarter-round.
• Acclimation — many products need to sit in the room before installation; follow the manufacturer’s instructions.

Common mistakes

• Measuring only the visible floor and forgetting closets.
• Using too small a waste factor for a patterned layout.
• Buying boxes from different production lots, which can differ slightly in color.
• Not keeping a spare box: replacement boards from the same run can be impossible to find later.

The flooring calculator and tile calculator do these steps automatically.