Square Footage Calculator
Calculate square footage for rooms, houses, flooring, and land. Supports rectangle, circle, triangle, and trapezoid shapes with unit conversion.
How to Use the Square Footage Calculator
- Select the shape of your room or space: Rectangle, Circle, Triangle, or Trapezoid.
- Enter the dimensions in feet: length and width for rectangles, radius for circles, base and height for triangles, or parallel sides and height for trapezoids.
- Optionally enter the price per square foot to estimate material or flooring costs.
- Click Calculate to see the total square footage and cost estimate.
- Use the Unit Converter tab if your measurements are in inches, meters, or yards.
Formula & Method
Rectangle / Square:Area = Length x Width
Circle:Area = π x Radius²
Triangle:Area = ½ x Base x Height
Trapezoid:Area = ½ x (Side A + Side B) x Height
Cost Estimate:Total Cost = Area x Price per Square Foot
Unit Conversions:
- 1 foot = 12 inches
- 1 foot = 0.3048 meters
- 1 yard = 3 feet
- 1 square foot = 144 square inches
- 1 square foot = 0.0929 square meters
Examples
| Room Type | Dimensions | Square Footage | Cost at $3/sq ft |
|---|---|---|---|
| Small bedroom | 10 ft x 12 ft | 120 sq ft | $360 |
| Master bedroom | 14 ft x 16 ft | 224 sq ft | $672 |
| Living room | 18 ft x 20 ft | 360 sq ft | $1,080 |
| Kitchen | 12 ft x 14 ft | 168 sq ft | $504 |
| Round dining area | Radius 8 ft | 201 sq ft | $603 |
| Triangular attic | Base 20 ft, Height 10 ft | 100 sq ft | $300 |
| 1,500 sq ft house | 30 ft x 50 ft (footprint) | 1,500 sq ft | $4,500 |
| 2,000 sq ft house | 40 ft x 50 ft (footprint) | 2,000 sq ft | $6,000 |
Frequently Asked Questions
How do I calculate square footage of a room?
Multiply the length by the width. For a room that is 12 feet by 15 feet, the square footage is 180 sq ft (12 x 15 = 180).
How do I calculate square footage for irregular shapes?
Break the room into simpler shapes (rectangles, triangles), calculate each area separately, then add them together. For L-shaped rooms, divide into two rectangles.
What is the average square footage of a house?
In the United States, the average new single-family home is about 2,500 square feet. However, this varies greatly by region, with urban homes typically smaller and suburban homes larger.
How many square feet is a 12x12 room?
A 12x12 room is 144 square feet. This is a common size for bedrooms and offices.
How do I convert square meters to square feet?
Multiply square meters by 10.764. For example, 20 square meters = 215.28 square feet.
Does square footage include walls?
No, square footage typically measures the interior floor area. Exterior dimensions are sometimes used for construction but interior dimensions give the usable space.
People Also Ask
How many square feet is a 20x20 room?
A 20x20 room is 400 square feet. This is a large room suitable for a great room, large living room, or small studio apartment.
How much flooring do I need for a 200 sq ft room?
You need at least 200 square feet of flooring. Add 10-15% extra (20-30 sq ft) for waste, cuts, and mistakes, so purchase 220-230 sq ft total.
What is the square footage of a 3-bedroom house?
A typical 3-bedroom house ranges from 1,200 to 2,500 square feet. The average is about 1,800-2,000 square feet in the US.
How do appraisers measure square footage?
Appraisers measure the exterior dimensions of the house and subtract non-heated areas like garages. They use ANSI standards and measure to the nearest inch.
Is a 10x10 room 100 square feet?
Yes, a 10x10 room is exactly 100 square feet. This is a common size for small bedrooms, home offices, and storage rooms.