Flooring Calculator
How many boxes of laminate, vinyl plank or hardwood to buy from room size, box coverage and a waste factor by layout pattern — plus total square feet and cost.
Flooring Calculator: with the default inputs, boxes to buy is 7.
For several rooms, add up their square footage and use Total area.
5–10% for a straight lay, 15% diagonal, 20% herringbone. See the table below.
Printed on the carton. Laminate/LVP is usually 18–24 sq ft; solid hardwood 18–22.
Material only. Leave 0 to skip cost.
- Square feet to buy (with waste)
- 132 ft²
- Floor area
- 120 ft²
- Area in the boxes you buy
- 140 ft²Whole boxes — the leftover is your attic stock for repairs.
- Material cost
- $0.00Priced on the full boxes you buy.
Assumptions
- Boxes are whole cartons; the calculator never assumes you can buy a partial box.
- Cost is material only, priced on the boxes purchased.
| Pattern / situation | Add | Why |
|---|---|---|
| Straight lay, simple rectangular room | 5–7% | End cuts get reused at the start of the next row. |
| Straight lay, room with closets, jogs or a hallway | 10% | More rows end in short, unusable pieces. |
| Diagonal (45°) | 15% | Every row starts and ends with an angled cut. |
| Herringbone or chevron | 20% | Angled cuts on all four sides of the field. |
| Wide plank or long-length hardwood | +3–5% | Fewer pieces per box means culled boards cost more. |
| Natural-grade or rustic hardwood | +5% | Expect to cull knots, checks and color outliers. |
Add the pattern percentage to any material-grade adjustment. Keep at least one unopened box for future repairs.
How this is worked out
The formula
Floor area = length × width (or your total) Area to buy = floor area × (1 + waste %) Boxes = area to buy ÷ coverage per box, rounded up Cost = boxes × coverage per box × price per sq ft
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Measure by
- For several rooms, add up their square footage and use Total area.Room length × width · Total area (More options)
- Room length
- A number.in ft, in, m, cm · 0 or more · defaults to 12
- Room width
- A number.in ft, in, m, cm · 0 or more · defaults to 10
- Waste factor
- 5–10% for a straight lay, 15% diagonal, 20% herringbone. See the table below.a percentage · from 0 to 50 · defaults to 10
- Coverage per box
- Printed on the carton. Laminate/LVP is usually 18–24 sq ft; solid hardwood 18–22.in ft², m² · 0.1 or more · defaults to 20
- Price per square foot
- Material only. Leave 0 to skip cost.in dollars · 0 or more · defaults to 0
- Total area(under More options)
- A number.in ft², m², yd² · 0 or more · defaults to 120
What you get back
- Boxes to buymain answer
- Square feet to buy (with waste)
- Floor area
- Area in the boxes you buy
- Whole boxes — the leftover is your attic stock for repairs.
- Material cost
- Priced on the full boxes you buy.
What this assumes
- Boxes are whole cartons; the calculator never assumes you can buy a partial box.
- Cost is material only, priced on the boxes purchased.
About this calculator
Flooring is priced per square foot but sold by the box, and every box you open produces offcuts, so the number you order is never the number on the tape measure. This calculator does the three steps installers do on the back of an envelope: room area, plus a waste factor for the layout, divided by what's in a carton — rounded up to whole boxes.
Measuring
Measure at floor level, wall to wall, into closets and doorways (flooring runs under the door to the threshold). For an L-shaped or multi-room job, work out each rectangle's square footage, add them up, and switch to Total area under More options. Don't subtract for kitchen islands or built-ins unless they're large; you'll want the material for cuts around them anyway.
Picking the waste factor
Waste depends far more on the layout than on the product:
- Straight lay in a plain room: 5–7%. The offcut from the end of one row starts the next, so very little is lost.
- Rooms with jogs, closets and hallways: 10%. This is the default and the right choice for most houses.
- Diagonal: 15%. Every row has two angled cuts.
- Herringbone or chevron: 20%. Beautiful, expensive, and unforgiving.
Add a few percent for natural-grade hardwood, where you'll cull boards for knots and color, and for very long planks where one bad board wastes more. Leaving one sealed box in the attic for a future repair is the best money you'll spend — dye lots change.
Boxes and coverage
Box coverage is printed on the carton and varies more than you'd expect: 7-in LVP might be 23.8 sq ft per box; 3¼-in solid oak 20; 12-mm laminate 17.6. Always use the number from the product you're buying, in the same units. The Area in the boxes you buy line shows what you'll actually own; the difference between that and the floor area is your working stock.
Cost
The cost figure prices the full boxes at your per-square-foot rate, because that's what the register will charge. Underlayment (typically $0.30–0.70 per sq ft), transitions, trim and installation are extra.
Frequently asked questions
▸How much extra flooring should I buy?
10% is the standard allowance for a straight lay in a typical room. Go to 15% for a diagonal layout and 20% for herringbone. Keep one unopened box afterwards for repairs.
▸How many boxes of flooring do I need for a 12×12 room?
144 sq ft plus 10% waste is 158.4 sq ft. At 20 sq ft per box that's 7.92, so buy 8 boxes. Check your carton's actual coverage — it's often 18–24 sq ft.
▸Does flooring go under kitchen cabinets and appliances?
Floating floors (laminate, click LVP) shouldn't be pinned under cabinets; run them up to the toe kick. Nailed or glued hardwood usually goes under. Either way, run flooring under the fridge and dishwasher.
▸Should I subtract the area of a closet or island?
Include closets — flooring goes in them. Don't bother subtracting an island under about 20 sq ft; the cuts around it use up the difference.
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