Square Footage Calculator
Calculate area in square feet for any shape - rectangles, circles, triangles, and more
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Area 1
Quick Answer
To calculate square footage: Length × Width = Square Feet. A 10×12 room = 120 sq ft. For circles: π × radius². For triangles: ½ × base × height.
Whether you're measuring a room for flooring, calculating land area for landscaping, or estimating paint coverage for walls, this square footage calculator handles any shape. Add multiple areas together for L-shaped rooms or complex spaces.
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Square Footage Formulas
| Shape | Formula | Example |
|---|---|---|
| Rectangle/Square | Length × Width | 10 × 12 = 120 sq ft |
| Circle | π × radius² | π × 5² = 78.54 sq ft |
| Triangle | ½ × base × height | ½ × 10 × 8 = 40 sq ft |
| Trapezoid | ½ × (base1 + base2) × height | ½ × (10+6) × 8 = 64 sq ft |
Unit Conversion Reference
| From | To | Multiply By |
|---|---|---|
| Square Feet | Square Yards | ÷ 9 |
| Square Feet | Square Meters | ÷ 10.764 |
| Square Feet | Square Inches | × 144 |
| Square Feet | Acres | ÷ 43,560 |
| Square Meters | Square Feet | × 10.764 |
| Acres | Square Feet | × 43,560 |
Common Room Sizes
| Room Type | Typical Size | Square Feet |
|---|---|---|
| Half Bathroom | 5×8 | 40 |
| Full Bathroom | 8×10 | 80 |
| Small Bedroom | 10×10 | 100 |
| Standard Bedroom | 12×12 | 144 |
| Master Bedroom | 14×16 | 224 |
| Living Room | 16×20 | 320 |
| Kitchen | 12×14 | 168 |
| 2-Car Garage | 20×22 | 440 |
Measuring Tips
- • Measure at floor level, not at the base of walls
- • For L-shaped rooms, divide into rectangles and add areas
- • Include closets if measuring for flooring or HVAC
- • For irregular walls, measure the longest points
- • Round up measurements for material ordering
- • Add 10% extra for flooring waste and cuts
- • Measure twice, calculate once
- • Use a laser measure for accuracy over 25 feet
Frequently Asked Questions
How do I calculate square footage?
For rectangles, multiply length by width (both in feet). For example, a 10×12 room = 120 square feet.
How many square feet in a square yard?
There are 9 square feet in 1 square yard. To convert sq ft to sq yd, divide by 9.
How do I calculate square footage of an L-shaped room?
Divide the L-shape into two rectangles, calculate each area separately, then add them together.
How many square feet in an acre?
There are 43,560 square feet in 1 acre.
How do I calculate square footage of a circle?
Use the formula π × radius². For a 10 ft diameter circle: π × 5² = 78.54 sq ft.
How do I convert square feet to square meters?
Divide square feet by 10.764 to get square meters. 100 sq ft = 9.29 sq m.
What is the formula for a triangle?
Area = 0.5 × base × height. A triangle with 10 ft base and 8 ft height = 40 sq ft.
How do I measure for flooring or carpet?
Measure length and width of each room, calculate square footage, and add 10% extra for waste and cuts.
Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
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