Flooring Calculator

Find out how much flooring you need in square feet and how many boxes of laminate, vinyl plank, hardwood or engineered flooring to buy, including waste.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: To find how much flooring you need, multiply room length by width for square feet, add 10% for waste, and divide by the coverage per box. A 12 x 10 ft room needs 132 sq ft including waste, which is 7 boxes at 20 sq ft per box.

Results

Flooring to buy: 132 sq ft; 120 sq ft floor area plus 10% waste
Boxes needed: 7 boxes; 140 sq ft purchased
Floor area: 120 sq ft; 13.33 sq yd

Flooring formula

Floor area (sq ft) = Length (ft) x Width (ft) + closets and hallways
Flooring to buy = Floor area x (1 + waste %)
Boxes = Flooring to buy / coverage per box, rounded up

Worked example

A 15 x 12 ft living room with a 3 x 6 ft closet: 180 + 18 = 198 sq ft. Add 10% waste for 217.8 sq ft. With boxes that cover 22.5 sq ft, 217.8 / 22.5 = 9.7, so buy 10 boxes (225 sq ft).

Quick reference

Flooring needed for common room sizes (10% waste, 20 sq ft boxes)
Room size	Floor area	With 10% waste	Boxes
10 x 10 ft	100 sq ft	110 sq ft	6
10 x 12 ft	120 sq ft	132 sq ft	7
12 x 12 ft	144 sq ft	158 sq ft	8
12 x 15 ft	180 sq ft	198 sq ft	10
15 x 20 ft	300 sq ft	330 sq ft	17
20 x 20 ft	400 sq ft	440 sq ft	22

How to measure a room for flooring

Measure the longest and widest points of the room in feet and multiply them for square footage. For L-shaped rooms, split the space into rectangles, calculate each and add them together. Include closets, doorways and any adjoining hall you plan to cover.

Flooring is sold by the box, and each box states its coverage in square feet. Divide your total by the box coverage and round up. Never round down: you cannot buy half a box, and a matching dye lot may not be available later.

How much waste to add

Add 10 percent for a standard straight-lay installation. Diagonal, herringbone or rooms with many angles and alcoves need 15 percent. Keep a few spare planks after the job for future repairs.

Key facts

Add 10% waste for straight-lay flooring and 15% for diagonal or herringbone patterns.
One square yard equals 9 square feet; carpet is often priced per square yard.
A typical box of laminate covers 18 to 24 sq ft; luxury vinyl plank covers 20 to 30 sq ft.
Always round boxes up. Dye lots vary, so buy every box for the job at the same time.

Frequently asked questions

How many boxes of flooring do I need for a 12x12 room?

A 12 by 12 room is 144 square feet. With 10% waste that is 158 square feet. At 20 square feet per box you need 8 boxes.

Should I add 10% or 15% for flooring waste?

Use 10% for straight layouts in simple rectangular rooms. Use 15% for diagonal or patterned layouts and rooms with lots of cuts.

Does the flooring calculator work for laminate, vinyl and hardwood?

Yes. It works for any flooring sold by the box: laminate, luxury vinyl plank, engineered and solid hardwood, and tile sold by square feet. Just enter the coverage printed on the box.

Sources and references

NWFA Wood Flooring Installation Guidelines (National Wood Flooring Association)
Laminate Flooring FAQs (North American Laminate Flooring Association)
Laminate flooring installation guide (Shaw Floors)

Next steps for this project

The usual order for a flooring & tile project. See all flooring & tile calculators.

Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.