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.
Results
- Flooring to buy
- 132 sq ft
- 120 sq ft floor area plus 10% waste
- Boxes needed
- 7 boxes
- 140 sq ft purchased, all from one lot number; the leftover in the last box is the repair stock
- Floor area
- 120 sq ft
- 13.33 sq yd. Measured wall to wall at the drywall, not the baseboard
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 upWorked 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
| 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 wall to wall at the drywall, not the baseboard, at the longest and widest points, and multiply for square footage. Split L-shaped rooms into rectangles and add them. Include closets, the doorway out to the next transition, and under the refrigerator and stove.
Flooring is sold by the box, and the box states its coverage. Divide the total by the box coverage and round up; the yard will not split a box. Order every box from one lot number and check the labels at pickup; a box from a later run is a shade off and can be a hair thicker.
How much waste to add
Add 10 percent for a straight lay. The waste is the end cut at each wall, the culls in every box and the rip on the last row; 48 in planks in a 10 ft room waste more than in a 16 ft room. Diagonal, herringbone and rooms with many jogs need 15 percent. Keep one unopened box for repairs; a matching lot will not be on the shelf in two years.
Solid and engineered hardwood needs 3 to 7 days in the room at living temperature and humidity before it goes down; laminate and vinyl plank need 48 hours. A full order comes on a 1,500 to 2,500 lb pallet dropped at the curb by liftgate; inside delivery is an added fee.
What this calculator leaves out
Underlayment, unless the plank has it attached. A transition or T-molding at each doorway, and quarter round or new baseboard to cover the 1/4 to 3/8 in expansion gap. Cleats or glue for hardwood, subfloor flattening to 3/16 in over 10 ft, and removal and disposal of the old floor. Stairs are bought per tread and nosing, not by the square foot.
Mistakes that cost money
- Mixing lot numbers: a box from a later run is a shade off and can be a hair thicker; order every box from one lot.
- Laying hardwood the day it arrives: solid and engineered need 3 to 7 days in the room at living conditions or joints gap or cup.
- Ordering square feet instead of boxes: 132 sq ft is 6.6 boxes and the yard sells 7; the 7th box is repair stock, not extra.
- Pallet delivery is curbside on a liftgate truck; 1,500 to 2,500 lb of boxes going upstairs is on you unless you pay for inside delivery.
- Subfloor out of flat by more than 3/16 in over 10 ft makes floating floors click and unlock; plane humps and fill dips first.
- Skipping the expansion gap: floating floors need 1/4 to 3/8 in at every wall and a T-molding past 30 to 40 ft, or they buckle.
Key facts
- Add 10% waste for straight-lay flooring and 15% for diagonal or herringbone; the waste is end cuts, culls and the last row rip.
- 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.
- Round boxes up and buy every box from one lot number; a box from a later run is a shade off and can be a hair thicker.
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 jogs. Every box has a few culls, so never go under 10%.
How long does flooring need to acclimate before installation?
Solid hardwood 3 to 7 days, engineered about 3 days, laminate and vinyl plank 48 hours. Stack it in the room where it goes at normal living temperature and humidity, not in the garage. Skipping it is the usual cause of gaps in winter and cupping in summer.
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.
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Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.