Interior & Finishing · Calculator
Square Footage Calculator
Use this square footage calculator to add up rooms and odd shapes, subtract islands and cutouts, and get square feet, square yards and square meters. Add a waste allowance and a price per square foot to estimate flooring.
Your space
- Area 1Part A lengthftinPart A widthftinPart B lengthftinPart B widthftin
Split the L into two rectangles that do not overlap and enter each one.
272 sq ft - Area 2(subtracted)LengthftinWidthftin
Squares and rectangles.
minus 18 sq ft
How to calculate square footage
Square footage is length times width, measured in feet. If you measure in feet and inches, convert the inches first: 12 ft 6 in is 12.5 ft. The calculator takes feet and inches directly, so you can type what the tape says.
Odd rooms are just several simple shapes. Split the floor into rectangles, triangles and circles, find each area, and add them. Anything inside the room that will not get flooring, like a kitchen island or a hearth, gets subtracted.
Every shape you enter is drawn to scale below the inputs. If the sketch does not look like your room, a measurement is off.
How to measure a room for flooring
- Sketch the room on paper, including closets, bump-outs and doorways where the new floor continues.
- Measure wall to wall at floor level, not at the baseboard top. Walls are rarely straight, so measure each dimension in two places and use the larger number.
- Round up to the next inch. Small rounding errors are absorbed by the waste allowance; a short measurement is not.
- Split L-shapes and alcoves into rectangles that do not overlap. Pick the split that gives you the easiest measurements.
- Note cutouts: islands, built-ins and fireplace hearths. Measure them and mark them as subtract.
Odd shapes: angles, bays and curves
Angled walls make a triangle on one side of the room. Measure the room as a rectangle up to where the angle starts, then add the triangle by measuring its three sides. No right angle needed.
Bay windows are trapezoids: the wall opening and the outside wall are the two parallel sides, and the depth is the distance between them.
Curves are rarely full circles. A half-round bump is half a circle, so enter the full circle and halve the number, or approximate it with a trapezoid.
| Shape | Where you see it | Measure |
|---|---|---|
| Rectangle | Most rooms, closets | Length, width |
| L-shape | Open plans, kitchens | Two rectangles |
| Triangle | Angled walls, corners | All three sides |
| Trapezoid | Bay windows, tapered halls | Both parallel sides, depth |
| Circle | Round rooms, curved bumps | Diameter |
How much extra flooring to buy
Every cut at a wall makes a scrap, and patterns make more. Waste depends on the material, the layout and how cut-up the room is. These are the usual allowances.
| Flooring and layout | Waste allowance | Notes |
|---|---|---|
| Vinyl plank or laminate, straight | 5 to 10% | 5% in a plain rectangle, 10% with closets and doorways |
| Hardwood, straight | 7 to 10% | More if boards have defects you will cull |
| Any plank, diagonal | 15% | Every wall cut is an angle cut |
| Herringbone or chevron | 15% | Some installers plan 20% for small rooms |
| Tile, straight grid | 10% | Add more for small rooms with many cuts |
| Large-format tile (24 in and up) | 15 to 20% | Fewer pieces per cut means more scrap |
| Carpet | 10% or more | Rolls come 12 ft wide, seams drive waste |
Cutting tile? Our best tile saws roundup covers wet saws for porcelain. For baseboard and transition strips, a miter saw makes clean, square cuts.
Square feet, square yards and square meters
1 square yard = 9 square feet. Carpet and some sheet vinyl are priced per square yard, so divide your square feet by 9 before comparing prices.
1 square meter = 10.764 square feet. Imported tile and some engineered flooring list coverage in square meters per box.
Walls are a different number. Floor square footage does not tell you how much paint or drywall you need. Use the paint calculator or the drywall calculator, which work from wall height and openings.
| Sq ft | Sq yd | Sq m |
|---|---|---|
| 50 | 5.56 | 4.65 |
| 100 | 11.11 | 9.29 |
| 150 | 16.67 | 13.94 |
| 200 | 22.22 | 18.58 |
| 250 | 27.78 | 23.23 |
| 500 | 55.56 | 46.45 |
| 1,000 | 111.11 | 92.90 |
Tips before you buy flooring
- Buy by the box, from one lot. Divide your total (with waste) by the coverage per box and round up. Check that every box has the same dye lot or run number.
- Keep a spare box. Discontinued flooring is impossible to match. One extra box makes future repairs easy.
- Let it acclimate. Wood and many laminates need a couple of days in the room before install. Follow the maker's instructions.
Measure carefully, subtract what will not be covered, and let the square footage calculator add the waste so you only make one trip to the store.
Frequently asked questions
How do you calculate square footage?
Multiply length by width in feet. A 12 x 14 ft room is 168 square feet. For odd shapes, split the space into rectangles, triangles and circles, find each area, and add them up.
How do I find the square footage of an L-shaped room?
Split the L into two rectangles that do not overlap, multiply length by width for each, and add the two areas. A 16 x 12 ft section plus an 8 x 10 ft section is 192 + 80 = 272 square feet.
How do you convert square feet to square yards?
Divide square feet by 9, because a square yard is 3 feet by 3 feet. 270 square feet is 30 square yards. Carpet is often priced per square yard, so this conversion matters.
How much extra flooring should I buy?
Buy 5 to 10 percent extra for a straight lay, 15 percent for diagonal or herringbone patterns, and up to 20 percent for large-format tile. Keep a full box after the job for future repairs.
Do I include closets and the area under cabinets?
Include closets and any floor that will be covered. Leave out the area under fixed cabinets and kitchen islands for most floating and tile floors, because the flooring stops at the cabinet base. Use the subtract option for those.
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