Rectangle Square Foot Calculator
Calculate rectangle square footage from length and width for rooms, floors, lots, walls, and other rectangular areas.
Rectangle Square Footage Calculator
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Rectangle Square Footage Formula
The rectangle square footage formula is Area = Length × Width. Both measurements must be in the same unit (feet) before multiplying. The result is expressed in square feet (ft²).
A rectangular floor 15 feet long and 12 feet wide equals 180 sq ft. This is the most common calculation for rooms, flooring, lots, walls, patios, and garden beds. The calculator also returns square meters, square yards, square inches, acres, and perimeter.
Why Use a Rectangle Calculator?
Most indoor and outdoor spaces are rectangular. Knowing the exact square footage of a rectangle helps you order the correct amount of flooring, paint, or turf — avoiding costly overruns or shortage trips to the hardware store.
How to Calculate Rectangle Square Feet
- Measure the length: Run a tape along the longest wall from corner to corner in feet.
- Measure the width: Measure the perpendicular wall in the same unit.
- Multiply: Length × Width = Square Feet.
- Add a waste factor: For flooring or tiling, add 10–15% to cover cuts and waste.
Common Rectangle Measurements
| Rectangle Size | Square Feet | Square Meters |
|---|---|---|
| 10 × 10 ft | 100 sq ft | 9.29 m² |
| 12 × 14 ft | 168 sq ft | 15.61 m² |
| 20 × 30 ft | 600 sq ft | 55.74 m² |
| 40 × 60 ft | 2,400 sq ft | 222.97 m² |
| 100 × 150 ft | 15,000 sq ft | 1,393.55 m² |
All Square Foot Calculators
Choose a specialized calculator for your specific project type.
Frequently Asked Questions
Multiply the length by the width. Both must be in feet. A rectangle 20 ft × 15 ft = 300 sq ft.
12 × 16 = 192 square feet (17.84 square meters).
Yes. Select your unit (feet, inches, meters, or centimeters) from the tabs. The calculator converts to square feet automatically.
Perimeter = 2 × (Length + Width). A 12 × 10 ft rectangle has a perimeter of 2 × (12 + 10) = 44 ft. This calculator shows perimeter alongside area.
Calculate the room area (length × width), then add 10–15% for waste. A 12 × 14 ft room = 168 sq ft + 10% = 184.8 sq ft of flooring to order.
Linear feet measures a single dimension (length). Square feet measures area (length × width). A room 12 ft long has 12 linear feet of one wall, but 144 square feet of floor if it is also 12 ft wide.