How Much Flooring Do I Need? Square Feet, Waste and Boxes by Room Size

You need the floor's square footage plus a waste allowance, divided by the coverage printed on the box. For a straight lay that allowance is usually 10%, so a 12 × 12 ft room (144 sq ft) needs about 159 sq ft of flooring, which is 8 boxes of a typical 20 sq ft carton. A 10 × 10 ft room needs about 6 boxes and a 15 × 20 ft living room about 17.

New to flooring? Start with What is flooring?, our overview of floor types, layers and installation, then come back here for the numbers.

The rest of this guide shows how to get that number for your own rooms, how much waste to add for different layouts, and why the box size on the label changes the count more than most people expect.

How much flooring do I need? The three-step formula

1. Square footage: length × width of each room, in feet. Split L-shapes into rectangles and add them.
2. Add waste: multiply by 1.10 for a straight lay (1.15 for diagonal, more for herringbone).
3. Boxes: divide by the square feet per carton and round up to a whole box.

Boxes = round up (room sq ft × 1.10 ÷ sq ft per box)

If you measured in inches, divide length × width by 144 to get square feet. In metric, 1 m² = 10.764 sq ft.

Flooring needed by room size

Straight lay with 10% waste. Box counts for three real carton sizes: 20 sq ft (a common laminate size), 22.09 sq ft (Pergo TimberCraft) and 17.32 sq ft (Pergo DuraCraft vinyl plank).

The same 12 × 12 room needs 8 boxes of one product and 10 of another. That is why you should never buy by box count from a friend's project or a store display: buy by the carton coverage of the exact floor you chose.

Box sizes vary more than you think

Carton coverage depends on plank width, length and how many planks the maker packs. Four products from one brand show the spread:

That is a 30% difference between the smallest and largest carton. Read "sq ft per carton" on the product page or the box end before you calculate, and enter it in the flooring calculator.

How much waste to add

Waste covers the end cuts at every wall, pieces that don't fit around door frames, damaged planks and a spare or two for repairs.

• Straight lay, simple room: 10% is the usual planning figure.
• Many corners, closets or short walls: 12–15%, because every wall end creates an offcut.
• Diagonal: about 15%.
• Herringbone or chevron: often 15–20% or more; check the maker's instructions.

Our waste factor guide compares the layouts on one 400 sq ft room.

Worked example: a bedroom and a hallway

A 12 × 14 ft bedroom and a 3 × 10 ft hallway get the same laminate, sold at 19.63 sq ft per carton.

1. Bedroom: 12 × 14 = 168 sq ft. Hallway: 3 × 10 = 30 sq ft. Total: 198 sq ft.
2. Add 10%: 198 × 1.10 = 217.8 sq ft.
3. Boxes: 217.8 ÷ 19.63 = 11.1, so buy 12 boxes (235.6 sq ft).

Round the pooled total, not each room. Rounding the bedroom (184.8 ÷ 19.63 = 9.4, so 10) and the hallway (33 ÷ 19.63 = 1.7, so 2) separately also gives 12 here, but with other sizes separate rounding often buys an extra box you didn't need.

What else to buy with the floor

Boxes of planks are only part of the order:

• Underlayment, unless the planks have a pad attached; see how much underlayment you need.
• Baseboard or quarter-round to cover the expansion gap at the walls; the baseboard calculator turns room size into boards.
• Transitions at doorways where the new floor meets another surface.
• A spare box if you want matching planks for future repairs. Products get discontinued.

Common mistakes

• Using the room's footprint from a listing. Listing square footage includes walls and spaces you won't floor. Measure each room yourself; how to measure a room for flooring covers closets, bay windows and angled walls.
• Forgetting closets. If the floor runs into the closet, add its area.
• Rounding each room separately. Pool rooms that use the same product, then round once.
• Assuming every box holds 20 sq ft. Check the carton; the table above shows how much it moves the count.
• Mixing production lots. Buy all boxes at once and check the lot number on each.

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