Flooring calculator
Add your rooms. For hard flooring you get square feet and boxes with waste; for carpet, the linear feet off the roll and the square yards, laid the way that wastes least.
Inputs
Result
Hard flooring
Plank flooring wastes the end of every row and the cuts around the room. 7% is enough for a plain rectangle laid straight, 10% for rooms with closets and doorways, and 15% for diagonal and herringbone layouts. Keep a spare box from the same lot for repairs.
Carpet
Carpet comes off a roll 12 ft wide, sometimes 15, and is sold by the square yard of what is cut, not of the room. A room up to 12 ft wide in one direction takes one strip; wider rooms take a second, seamed strip, and the offcut is usually waste. The calculator tries both directions and keeps the one that uses less.
A 14 by 13 ft room is 182 sq ft, but off a 12 ft roll it takes two strips 13 ft long: 26 linear feet, or 34.7 sq yd. That waste is why carpet quotes look high for awkward room sizes.
Questions
How much flooring do I need?
The room's area plus 7 to 15% for cuts, depending on the layout, rounded up to whole boxes. A 12 x 15 ft room is 180 sq ft, so about 198 sq ft with 10%.
How many boxes of flooring do I need?
The area with waste divided by the coverage on the carton. 198 sq ft of planks at 20 sq ft a box is 10 boxes.
How do I calculate carpet in square yards?
Work out the length of carpet cut from the roll, multiply by the roll width and divide by 9. A 12 x 15 ft room off a 12 ft roll takes 15 ft, which is 20 sq yd.
How much extra carpet should I buy?
It depends on seams more than on percentage. Rooms wider than the roll need a second strip, so measure both directions and let the calculator pick the cheaper one.
How much extra laminate or vinyl plank should I buy?
7 to 10% for straight installs and 15% for diagonal or herringbone.
More Interiors calculators
Drywall calculator
Sheets of drywall for a room or a wall area, with screws, joint compound and tape.
Paint calculator
Gallons of paint and primer for a room or wall area, by coats and the coverage on the can.
Insulation calculator
How much attic insulation to add for your climate zone, in R-value and depth, by ENERGY STAR's recommendations.
Tile calculator
Tiles and boxes for a floor or wall, with grout by joint size and thinset by trowel.