Square Footage Calculator

Calculate room area in sq ft, sq meters, and sq yards

ft
ft
Total Area
300.00 ft²
20 × 15 ft rectangle
Square Feet300.00 ft²
Square Meters27.87 m²
Square Yards33.33 yd²
Square Inches43,200 in²

How to Measure Square Footage

Use a tape measure to find the length and width of the room in feet. Measure from wall to wall at the widest points. Multiply length × width for the area in square feet.

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Flooring tip: Always add 10% extra to your square footage for cuts, waste, and pattern matching.

For irregular rooms, break the space into rectangles and add the areas together — use L-Shape mode above for rooms with one corner cutout.

Formulas by Shape

Rectangle: Area = Length × Width
Triangle: Area = ½ × Base × Height
Circle: Area = π × Radius² (π ≈ 3.14159)
L-Shape: Area = Rectangle A + Rectangle B

Common Room Sizes

Room TypeTypical SizeSquare Footage
Small Bedroom10×10 ft100 ft²
Standard Bedroom12×12 ft144 ft²
Master Bedroom14×16 ft224 ft²
Living Room15×18 ft270 ft²
Large Living Room20×20 ft400 ft²
Kitchen10×12 ft120 ft²
Bathroom5×8 ft40 ft²
Garage (1-car)12×20 ft240 ft²
Garage (2-car)20×22 ft440 ft²

Unit Conversions

FromToMultiply By
Square feet (ft²)Square meters (m²)× 0.0929
Square feet (ft²)Square yards (yd²)÷ 9
Square feet (ft²)Square inches (in²)× 144
Square feet (ft²)Acres÷ 43,560
Square meters (m²)Square feet (ft²)× 10.764

What Can You Calculate?

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Flooring
Hardwood, tile, or carpet
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Painting
1 gallon ≈ 350 sq ft wall
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Real Estate
Compare home sizes
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Solar Panels
Roof coverage planning
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Garden / Lawn
Fertilizer & grass seed
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Storage
Furniture layout planning

Common Square Footage Measurement Mistakes

  • Not adding 10% waste factor — always order 10–15% extra flooring for cuts, mistakes, and pattern matching. Otherwise you may run short.
  • Mixing inches and feet — a room that is 12 feet 6 inches wide is 12.5 feet — NOT 12.6. Convert inches to decimal feet first (inches ÷ 12).
  • Measuring to the wrong point — for flooring, measure wall to wall at the widest point. For paint, measure the wall height × width including the trim area.
  • Forgetting odd-shaped rooms — break L-shaped or irregular rooms into rectangles, calculate each separately, then add them together.

Why Square Footage Calculations Matter

  • Flooring and tiling — accurate square footage prevents over-ordering expensive materials or running short mid-project.
  • Paint estimation — one gallon covers roughly 350–400 sq ft. Knowing your wall area tells you exactly how many gallons to buy.
  • Real estate — home listings show square footage; buyers compare price per square foot to assess value.
  • HVAC sizing — heating and cooling systems are sized to the square footage of the space they need to condition.

Frequently Asked Questions

How many square feet is a 12×12 room?

A 12×12 room is 144 square feet. Calculation: 12 ft × 12 ft = 144 ft².

How much flooring do I need for a 300 sq ft room?

Buy approximately 330 sq ft of flooring (300 × 1.10). Always add 10% for waste, cuts, and future repairs.

How do I convert square feet to square meters?

Multiply by 0.0929. Example: 300 ft² × 0.0929 = 27.87 m². The calculator shows this automatically.

What is a square foot?

A square foot is a 1 ft × 1 ft square area. It is the standard unit for measuring room sizes, flooring, and real estate in the United States.

How many square feet are in an acre?

There are 43,560 square feet in 1 acre. To convert acres to sq ft, multiply by 43,560. For example, 0.5 acres = 21,780 sq ft. An acre is roughly the size of a football field (without the end zones).

How many square feet is a 10×10 room?

A 10×10 room is 100 square feet. Calculation: 10 ft × 10 ft = 100 ft². This is a typical small bedroom or large bathroom size.

How big is 1,000 square feet?

1,000 square feet is roughly the size of a small apartment or a 2-bedroom home. It could be a 25 ft × 40 ft space, or a 20 ft × 50 ft layout. The average US apartment is about 882 sq ft.

How do I calculate square footage from inches?

Measure in inches, multiply length × width to get square inches, then divide by 144 to get square feet. Formula: sq ft = (inches × inches) ÷ 144. Or enter measurements in feet using decimals (e.g., 6 inches = 0.5 ft).

How many square feet is a 20×20 room?

A 20×20 room is 400 square feet. This is the size of a large master bedroom or a small studio apartment.