Square Footage Calculator for Contractors
Length times width, repeated for as many areas as the job has. It also gives square yards, because carpet is still quoted that way in much of the country, and perimeter, because trim and baseboard are not.
Worked example
These are the figures the calculator opens with and the answer it gives. Change anything above and every number below moves with it.
- Length14 ft
- Width12 ft
- How many rooms or areas this size1
- Extra area to add0 sq ft
Total area168 sq ft
| One area | 168 sq ft |
|---|---|
| Times 1, plus extra | 168 sq ft |
| Square yards | 18.67 |
| Square meters | 15.61 |
| Perimeter of one area | 52 ft |
What this calculator assumes
- Length times width, times how many areas are that size. For an L shaped room, split it into two rectangles and run this twice.
- Square yards are square feet divided by nine, which is how carpet is still quoted in much of the country.
Rooms that are not rectangles
Split the space into rectangles and add them. An L shaped room is two rectangles, a bay window is a rectangle plus a triangle, a hallway is its own rectangle. Run this once per piece and add the results in the extra field.
For a triangle, take half the base times the height. For a circle, 3.1416 times the radius squared. Those two cover nearly everything a residential job will throw at you.
Which square footage the customer means
Gross living area, the number on the listing, is measured to the outside of the exterior walls and excludes the garage and anything below grade. It is not the number you order flooring against.
For material, you want the finished floor area inside the walls, which is always smaller. When a homeowner says the house is 2,400 square feet and the flooring measures 2,050, neither of you is wrong, you are measuring different things. Say which one you used in the estimate and the argument never starts.
Questions people ask
How do I calculate square footage of an L shaped room?
Split it into two rectangles at the inside corner, measure each one, and add them. This calculator has a field for extra area so you can run the bigger rectangle and add the smaller.
How many square feet are in a square yard?
Nine. A square yard is 3 feet by 3 feet. To convert square feet to square yards, divide by nine.
Free Contractor Estimate Template, free, no signup, PDF Word and Excel.
Common sizes, worked out
The same calculator with the numbers already filled in, one page per size, each ending in its own material list.
More sizes, answered
Each row is this calculator run with those numbers when the page was built. Type the same numbers in above to see every line of the working.
| Example | What it assumes | Total area |
|---|---|---|
| 8x8 room | Eight feet by eight feet. | 64 sq ft |
| 9x12 room | Nine feet by twelve feet. | 108 sq ft |
| 11x11 room | Eleven feet by eleven feet. | 121 sq ft |
| 12x14 room | Twelve feet by fourteen feet. | 168 sq ft |
| 13x13 room | Thirteen feet by thirteen feet. | 169 sq ft |
| 12x16 room | Twelve feet by sixteen feet. | 192 sq ft |
| 10x20 room | Ten feet by twenty feet. | 200 sq ft |
| 12x18 room | Twelve feet by eighteen feet. | 216 sq ft |
| 14x16 room | Fourteen feet by sixteen feet. | 224 sq ft |
| 12x20 room | Twelve feet by twenty feet. | 240 sq ft |
| 12x24 room | Twelve feet by twenty four feet. | 288 sq ft |
| 16x20 room | Sixteen feet by twenty feet. | 320 sq ft |
| 20x24 garage | Twenty feet by twenty four feet. | 480 sq ft |
| 24x24 room | Twenty four feet by twenty four feet. | 576 sq ft |
| 30x40 shop | Thirty feet by forty feet. | 1,200 sq ft |