Square Footage Calculator
Use this calculator to quickly estimate total area based on length and width.
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Square Footage Calculator
📐 Formula Used
Area (sq ft) = Length (ft) × Width (ft)
Total Area
0 sq ft
Enter measurements above to calculate
Square Feet
0
Square Yards
0
Square Meters
0
Square Inches
0
For multiple rooms or areas: calculate each rectangle separately, then add the results together.
How to Calculate Square Footage
Square footage is the area of a flat surface measured in square feet. For any rectangular room or area, multiply the length by the width. It's the most common measurement used when buying flooring, paint, tile, sod, and many other materials.
Steps:
- Measure the length of the room or area in feet using a tape measure.
- Measure the width in feet.
- Multiply: Length × Width = Square Feet.
- For L-shaped or irregular rooms, divide into rectangles, calculate each, and add together.
💡 Pro Tip
Always measure to the nearest inch for accurate results. Convert inches to decimal feet by dividing by 12. For example, 15 ft 6 in = 15.5 ft. Most materials add 10% waste — so order more than your exact square footage.
Square Footage Formulas for Other Shapes
| Shape | Formula | Example |
|---|---|---|
| Rectangle | Length × Width | 15 × 12 = 180 sq ft |
| Square | Side² | 10² = 100 sq ft |
| Triangle | ½ × Base × Height | ½ × 10 × 8 = 40 sq ft |
| Circle | π × Radius² | 3.14159 × 5² = 78.5 sq ft |
| Trapezoid | ½ × (Base1 + Base2) × Height | ½ × (10+14) × 6 = 72 sq ft |
What to Use Square Footage For
- Flooring — calculate sq ft then add 10% waste for hardwood, LVP, tile, and carpet
- Paint — walls: 2 × (L + W) × ceiling height minus doors/windows
- Tile — room area + 10–15% for cuts and waste
- Sod / Grass seed — lawn area for ordering the right amount
- Mulch / Topsoil — area then depth to calculate cubic yards
- Roofing — roof area (in "squares" = 100 sq ft each)
- Insulation — attic or wall area for batt or blown-in insulation
Frequently Asked Questions
How do I calculate square footage of a room?
Measure the length and width of the room in feet, then multiply: Length × Width = Square Feet. For a 15 ft × 12 ft room: 15 × 12 = 180 sq ft. For L-shaped rooms, split into two rectangles, calculate each, and add them together.
How many square feet is a 10×10 room?
A 10×10 ft room is 100 square feet. A 12×12 room is 144 sq ft. A 15×15 room is 225 sq ft. A 20×20 room is 400 sq ft.
How do I convert square feet to square yards?
Divide square feet by 9 to get square yards (since 1 yard = 3 feet, 1 sq yd = 9 sq ft). For example, 180 sq ft ÷ 9 = 20 sq yards. Carpet is often priced by the square yard.
How do I convert square feet to square meters?
Multiply square feet by 0.0929 to get square meters. For example, 180 sq ft × 0.0929 = 16.72 sq meters.
How much flooring do I need for 200 square feet?
Order your room's square footage plus 10% waste — so 200 sq ft needs 220 sq ft of flooring ordered. For diagonal installations, add 15% instead. Use our Flooring Cost Calculator to estimate total material and installation cost.