How the square footage calculator is calculated
total area = the sum of every section
with waste = total area × (1 + waste percent)
Worked example: four rooms
These are the example defaults loaded in the calculator above: four rooms of 14 x 12, 12 x 10, 10 x 10 and 8 x 6 feet, plus 10% waste.
| Line | Amount |
|---|---|
| 14 x 12 ft | 168 sq ft |
| 12 x 10 ft | 120 sq ft |
| 10 x 10 ft | 100 sq ft |
| 8 x 6 ft | 48 sq ft |
| Total measured area | 436 sq ft |
| Waste at 10% | 43.6 sq ft |
| Area with waste | 479.6 sq ft |
Every default in the calculator is an example so you can see a result straight away. None is a market average. Replace each with your own costs and rates.
Finding the square footage of an L-shaped room
Draw the room on paper and cut it into rectangles. An L-shape is two rectangles. Measure the length and width of each, enter them as two sections, and the calculator adds them. If two sections share a wall, make sure the same strip of floor is not counted twice.
How much waste to add
Waste depends on the material and the room, not on a fixed rule. Straight cuts across an open floor waste little. Diagonal layouts, patterned material and rooms with many corners waste more. Use the figure your supplier or installer gives you for the material you are buying. The 10% default is only an example.
Square feet, square yards and square meters
One square yard is 9 square feet, because a yard is 3 feet on each side. One square meter is about 10.764 square feet. The calculator shows all three so you can match whatever unit your supplier prices in.
Turn this into an estimate or invoice
The button under the result carries the area, with your waste added, into the document generator as one line you can price per square foot. To price the whole job section by section, open the cost estimator. If you work in a trade, the contractor invoice page has designs and presets.
Related calculators
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- Painting estimate calculatorWall area, coats and a labor price
- Mulch calculatorBed area and depth into cubic yards and bags
Questions people ask
How do I calculate square footage of a room?
Multiply the length by the width, both in feet. A room 14 feet by 12 feet is 168 square feet. For a room with several parts, work out each rectangle and add them.
How do I find the square feet of an L-shaped room?
Split the L into two rectangles, multiply length by width for each, and add the two areas. Enter each rectangle as its own section in the calculator and it adds them for you.
How many square feet are in a square yard?
There are 9 square feet in a square yard, since a yard is 3 feet long and 3 feet wide.
How much waste should I add?
It depends on the material and the layout. Suppliers and installers often quote a figure for the product you are buying, so ask for it. The calculator defaults to 10% as an example, and you can change it.
Can I measure in inches or meters?
Yes. Choose the unit above the measurements. The calculator converts every section to square feet and also shows square yards and square meters.