ConstructionInstant Tool
Square Footage Calculator
Calculate square footage for flooring, rooms, painting, landscaping, and materials.
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How Square Footage Calculator Works
Square Footage sq ft = Length in feet × Width in feetTo find the square footage of any rectangular area, multiply length in feet by width in feet. For circular spaces, area equals π multiplied by radius squared. For triangular spaces, area equals 0.5 multiplied by base times height. Add an optional waste factor to guarantee sufficient materials during installation.
Variable Breakdown
L
LengthLength of the surface in feet
W
WidthWidth of the surface in feet
r
RadiusHalf of the diameter for circular spaces in feet
Waste
Waste PercentageAllowance for edge cuts, pattern matching, and installation trimming
Example Calculation
Master Bedroom Hardwood Flooring
A rectangular master bedroom measuring 15 feet long by 12 feet wide with a 10% hardwood installation waste allowance.
- Multiply length by width: 15 ft × 12 ft = 180.00 sq ft base area.
- Add 10% waste factor: 180 sq ft × 1.10 = 198.00 sq ft total material.
- Convert to square yards: 180 sq ft ÷ 9 = 20.00 sq yd.
- Convert to square meters: 180 sq ft × 0.092903 = 16.72 m².
Result:198.00 sq ft total material required
Square Footage Coverage Reference
| Application | Standard Dimensions | Square Footage | Recommended Waste |
|---|---|---|---|
| Standard Bedroom | 12 ft × 14 ft | 168 sq ft | 10% |
| Two Car Garage | 20 ft × 20 ft | 400 sq ft | 5% |
| Large Living Room | 16 ft × 20 ft | 320 sq ft | 10% |
| Herringbone Tile Room | 12 ft × 12 ft | 144 sq ft | 15% |
| Standard Bathroom | 8 ft × 10 ft | 80 sq ft | 15% |
Frequently Asked Questions
How do you calculate square footage of a room?
Measure the length and width of the room in feet. Multiply length by width to obtain square footage. For example, a 12 ft by 15 ft room is 180 sq ft.
How do you convert square inches to square feet?
Divide total square inches by 144 since 1 foot equals 12 inches and 144 square inches make one square foot.
How much extra material should I add for waste factor?
Industry standard recommends adding 10% for rectangular rooms, and 15% for rooms with odd angles, diagonal cuts, or herringbone tile patterns.
How many square feet are in a square yard?
There are 9 square feet in one square yard where 3 ft by 3 ft equals 9 sq ft. To convert square feet to square yards, divide your square footage by 9.
How do you calculate square footage of an irregular room?
Break the irregular space into separate rectangular or triangular sections, calculate the square footage of each section, and add the totals together.
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