To calculate flooring, multiply each room's length by its width in feet, add the rooms together, add about 10% for cutting waste (15% for herringbone), and divide by the square feet per box. A 12 × 12 ft room is 144 sq ft; with 10% extra you need 158.4 sq ft, which is 8 boxes of 20 sq ft.
This flooring square feet calculator is for anyone buying laminate, vinyl plank, engineered or solid hardwood, tile or carpet. Enter one rectangle per line, so an L-shaped room or a whole floor of rooms is just a few lines. It returns the floor area, the waste for your layout, boxes, square yards for carpet, square meters, and cost by the square foot, the box or the square yard.
How to measure and use the calculator
- Measure each room wall to wall at floor level. Round up to the next inch or half foot; it is better to have a little over than to run short.
- Enter each room as length, width, one per line. For an L-shaped or T-shaped room, split it into rectangles that don't overlap.
- Pick the layout. The waste fills in for straight planks, diagonal, or herringbone and chevron, or choose custom if your product's instructions give a number.
- Enter the coverage per box from the carton. Add a price per square foot, per box or per square yard to see the cost.
The formula
Floor area = Σ (length × width) for each rectangle. Area to buy = floor area × (1 + waste ÷ 100). Boxes = area to buy ÷ coverage per box, rounded up. Square yards = square feet ÷ 9 and square meters = square feet × 0.09290304, both exact by definition in NIST Handbook 44. If you measure in meters, the calculator converts with 1 ft = 0.3048 m.
Waste factor by layout
Waste is the flooring lost to cuts at walls, doorways and pattern ends. The figures below come from Havwoods' published wastage guidance for wood flooring, except diagonal, which is our labeled assumption. Your flooring manufacturer's installation guide comes first if it gives a different number.
| Layout | Under 100 m² (1,076 sq ft) | 100 m² and over | Source |
|---|---|---|---|
| Straight plank | 10% | 7% | Havwoods wastage guide |
| Diagonal (assumption) | 15% | 15% | Assumption (no verified source) |
| Herringbone / chevron | 15% | 12% | Havwoods wastage guide |
Rooms with many corners, closets and doorways create more offcuts than a plain rectangle, so add a few points of waste for them if you are unsure. Keep a box of leftovers for repairs; matching a discontinued color later is hard.
Flooring square feet by room size
For a single rectangular room with a straight plank layout at 10% waste. Boxes assume 20 sq ft cartons as an example; enter your own carton size in the calculator.
| Room | Sq ft | +10% waste | +15% (herringbone) | Boxes (20 sq ft) | Sq yd (carpet) | m² |
|---|---|---|---|---|---|---|
| 10 × 10 ft | 100 | 110 | 115 | 6 | 11.11 | 9.29 |
| 10 × 12 ft | 120 | 132 | 138 | 7 | 13.33 | 11.15 |
| 12 × 12 ft | 144 | 158.4 | 165.6 | 8 | 16 | 13.38 |
| 12 × 14 ft | 168 | 184.8 | 193.2 | 10 | 18.67 | 15.61 |
| 12 × 16 ft | 192 | 211.2 | 220.8 | 11 | 21.33 | 17.84 |
| 14 × 16 ft | 224 | 246.4 | 257.6 | 13 | 24.89 | 20.81 |
| 15 × 20 ft | 300 | 330 | 345 | 17 | 33.33 | 27.87 |
| 16 × 20 ft | 320 | 352 | 368 | 18 | 35.56 | 29.73 |
| 20 × 20 ft | 400 | 440 | 460 | 22 | 44.44 | 37.16 |
| 20 × 24 ft | 480 | 528 | 552 | 27 | 53.33 | 44.59 |
Square feet to square yards and square meters
Carpet quotes often use square yards, plank cartons list square feet, and metric plans use square meters. One square yard is 9 sq ft and one square foot is 0.09290304 m².
| Square feet | Square yards | Square meters |
|---|---|---|
| 50 | 5.56 | 4.65 |
| 100 | 11.11 | 9.29 |
| 144 | 16 | 13.38 |
| 200 | 22.22 | 18.58 |
| 250 | 27.78 | 23.23 |
| 300 | 33.33 | 27.87 |
| 500 | 55.56 | 46.45 |
| 750 | 83.33 | 69.68 |
| 1,000 | 111.11 | 92.9 |
| 1,500 | 166.67 | 139.35 |
| 2,000 | 222.22 | 185.81 |
Worked examples
L-shaped living room
Split into a 16 × 12 ft rectangle (192 sq ft) and a 10 × 8 ft alcove (80 sq ft): 272 sq ft. At 10% for straight planks: 299.2 sq ft, 15 boxes of 20 sq ft, or 33.24 sq yd if it is carpet.
Four rooms on one floor
12 × 12, 14 × 10, 20 × 16 and 12 × 11 ft add up to 736 sq ft. That is under 100 m² (68.4 m²), so the straight-plank waste is 10%: 809.6 sq ft, 41 boxes of 20 sq ft.
Herringbone in a 15 × 12 ft dining room
180 sq ft at 15% waste is 207 sq ft, 11 boxes. The same room laid straight would need 198 sq ft, so the pattern costs about 9 sq ft of extra material.
Metric room
A 5 × 4 m bedroom is 20 m², 215.3 sq ft. With 10% waste: 236.8 sq ft (22 m²).
Measuring irregular rooms
Most floors break into rectangles, but a few shapes need a different approach. Sketch the room on paper first, write each measurement on the sketch, and then turn it into lines for the calculator.
- L, T and U shapes. Draw one straight line across the narrow part so the room becomes two or three rectangles. Each rectangle is one line in the calculator.
- Angled walls. Measure the room as the full rectangle that contains the angle, then subtract the missing triangle (½ × its two short sides). Or treat the angled corner as a full rectangle and let the extra area act as waste; the difference is usually a few square feet.
- Bay windows and curved walls. Measure the bay as a rectangle to the deepest point. The small overcount covers the angled cuts the bay will need.
- Hallways and doorways. Measure halls as their own rectangles. If the flooring continues through a doorway, add the door opening as a thin rectangle (the door width × the jamb depth you measure); if a threshold separates two floors, stop at the threshold.
- Closets. A reach-in closet is a small rectangle on its own line. A walk-in closet is just another room.
Before you order
Run the calculation twice: once with your measurements and once after a second person re-measures. A transposed digit costs more than any waste factor. Check the coverage on the actual carton you will buy, because two products from the same brand can hold a different area per box. If the carton prints a production run or lot number, buy all boxes from the same run so color and texture match, and keep one spare box after the job for repairs. Ask the store about its return policy for unopened boxes; rounding up to a full extra box is usually cheaper than running short and waiting for a reorder.
For carpet, the waste comes from the roll width and seams rather than from cutting each piece, so a carpet installer's seam layout can need more than the square-yard figure here. Use this calculator's square yards as a starting point and confirm with the installer's measurement.
Common mistakes
- Overlapping rectangles. When splitting an L-shape, cut it along one line so no area is counted twice.
- Rounding boxes down. You can't buy part of a box. 9.2 boxes means 10.
- Assuming every box holds the same area. Carton coverage varies with plank size and product line; read the label.
- Forgetting transitions and stairs. Stairs, thresholds and reducers are bought by the piece or linear foot, not by the square foot.
- Mixing up square feet and square yards. A carpet quote per square yard looks nine times higher than the same price per square foot.
For baseboards and quarter round, measure the room perimeter with the linear feet calculator. Painting at the same time? The paint calculator works out the walls, and the renovation cost calculator helps budget the whole project. For a self-leveling underlayment pour, the cubic feet calculator gives the volume.
Frequently asked questions
How do I calculate flooring square feet?
Multiply length × width in feet for each room and add the rooms together. A 12 × 12 ft room is 144 sq ft. Add waste for cuts: at 10% for a straight plank layout you buy 158.4 sq ft.
How do I measure an L-shaped room for flooring?
Split it into two rectangles that don't overlap and add them. A room made of a 16 × 12 ft section and a 10 × 8 ft section is 192 + 80 = 272 sq ft, or 299.2 sq ft with 10% waste.
How much extra flooring should I buy?
Havwoods, a wood flooring supplier, recommends 10% for straight plank layouts and 15% for herringbone or chevron in areas under 100 m² (1,076 sq ft), and 7% and 12% for larger areas. We use 15% for diagonal layouts as an assumption; no manufacturer figure we could verify covers it.
How many boxes of flooring do I need?
Divide the square feet with waste by the coverage printed on the carton and round up. For 158.4 sq ft and 20 sq ft boxes that is 8 boxes; with 23.5 sq ft boxes it is 7. Box sizes vary by product, so always use the number on your carton.
How do I convert square feet to square yards for carpet?
Divide by 9, because 1 square yard = 9 square feet (NIST Handbook 44). A 12 × 12 ft room is 16 sq yd; with 10% waste, 17.6 sq yd.
How many square meters is my floor?
Multiply square feet by 0.09290304. 144 sq ft is 13.38 m². Going the other way, a 5 × 4 m room is 20 m², or 215.3 sq ft.
How much flooring for a 12 × 12 room?
144 sq ft of floor, so buy 158.4 sq ft at 10% waste: 8 boxes of 20 sq ft. Laid in herringbone at 15% it is 165.6 sq ft.
Should I include closets?
Yes, if the flooring runs into them. Measure each closet as its own rectangle. Skip areas under fixed cabinets or a kitchen island if the flooring stops at them.
Why does the waste drop for big areas?
Offcuts from one row can start the next, so the share lost to cuts falls as the area grows. Havwoods lowers its figures from 10% to 7% (plank) and 15% to 12% (herringbone) above 100 m², about 1,076 sq ft. The calculator applies that switch automatically.
Sources & method
- NIST Handbook 44 (2026), Appendix C — 1 yd² = 9 ft²; 1 ft² = 0.092 903 04 m²; 1 ft = 0.3048 m
- NIST SP 811, Guide for the Use of the International System of Units — area conversion factors
- Havwoods — Everything you need to know about wastage (10% plank, 15% herringbone/chevron under 100 m²; 7% and 12% above)
Results are estimates for general information. Found an error? It helps everyone — see our methodology.