Flooring calculator

How to use

1. Measure the room: Length and width at floor level, in feet and inches.
2. Add closets: Enter the area of closets, nooks or a hallway that get the same floor.
3. Choose the layout: Straight, diagonal or herringbone sets the waste allowance; add more for obstacles.
4. Read the carton: Enter the square feet per box and, if you like, the price per square foot.

How to measure a floor

Sketch the room with its doorways and closets. Measure the longest and widest parts at floor level, not along the baseboards, because walls may not be straight. Split an L-shaped room into rectangles and add closets and nooks that get the same floor.

Waste allowance

Flooring has to be cut to fit walls and objects, so you buy more than the floor area. LL Flooring's estimating guide adds 7 to 10% for a straight lay, 15% for a diagonal lay and 15 to 20% for herringbone or complex patterns, and 3 to 5% more for rooms with numerous obstacles such as vents or a fireplace. MSI adds 10% for mistakes, cuts and damage; Armstrong's laminate instructions use 10% for wood visuals and 15% for tile visuals.

Boxes and plank direction

Divide the total by the coverage printed on the carton and round up; MSI notes that most vinyl plank boxes cover 18 to 25 sq ft. Buy all the boxes at once with matching run or lot numbers.

MSI recommends laying planks parallel to the flow of high-traffic areas and staggering end joints by at least 6 in. A straight lay in either direction needs about the same amount of material.

How it is calculated

• Floor area = length × width (inches ÷ 12 first) + closets and extra areas
• Flooring needed = floor area × (1 + waste % + obstacle %)
• Boxes = flooring needed ÷ coverage per box, rounded up

Examples

10 × 12 ft bedroom with a closet

120 sq ft plus a 5 × 2 ft closet = 130 sq ft. With 10% waste that is 143 sq ft; at 20 sq ft per box, 7.15 boxes, so buy 8 boxes (160 sq ft).

Same room, herringbone

130 sq ft plus 20% is 156 sq ft, still 8 boxes of 20 sq ft, with only 4 sq ft spare.

Frequently asked questions

How much flooring do I need?

Multiply the room's length by its width in feet, add closets, add the waste allowance and divide by the square feet per box. Round the boxes up. A 10 × 12 ft room with a 10 sq ft closet needs 143 sq ft at 10% waste.

How much extra flooring should I buy?

LL Flooring gives 7 to 10% for a straight lay, 15% for diagonal and 15 to 20% for herringbone or complex patterns, plus 3 to 5% for rooms with many obstacles. Armstrong's laminate instructions add 10% for wood looks and 15% for tile looks.

How many square feet are in a box of flooring?

It depends on the product and is printed on the carton. MSI says most luxury vinyl plank boxes cover 18 to 25 sq ft.

Which way should flooring planks run?

MSI recommends laying vinyl planks parallel to the flow of high-traffic areas, starting along the room's most prominent wall. The direction hardly changes the quantity for a straight lay; a diagonal lay needs more.

Should I buy an extra box?

Rounding up usually leaves a few planks over. Keep them: LL Flooring recommends buying a small additional amount for future repairs, and a later batch may not match.

Is this different from the square footage calculator?

The square footage calculator gives floor, wall and ceiling areas. This one starts from the floor area and turns it into whole boxes with a waste allowance and an optional cost.

Sources

• Estimating Your DIY Flooring Project, LL Flooring (Lumber Liquidators)
• How To Measure Your Space For Luxury Vinyl Flooring, MSI Surfaces
• Lock&Fold Locking Laminate Planks: Installation Instructions, Armstrong Flooring (hosted by Lowe's)