Square Footage Calculator
Calculate square footage of rectangles, circles, triangles, trapezoids and more. Free online square footage calculator with price per square foot option.
The Square Footage Calculator helps you estimate the area of various shapes including rectangles, circles, triangles, trapezoids, and more. Whether you are planning a home renovation, installing flooring, painting a room, or landscaping a yard, calculating square footage accurately is essential for estimating material quantities and costs. For land area conversions, try our Square Feet to Acres Converter and Area Calculator.
What is Square Footage?
Square footage is a measurement of area expressed in square feet (sq ft). It represents the amount of two-dimensional space a surface occupies. Square footage is commonly used in real estate, construction, interior design, and landscaping to describe the size of properties, rooms, and outdoor spaces.
How to Calculate Square Footage
The formula for calculating square footage depends on the shape of the area:
- Rectangle: Length × Width
- Circle: π × (Diameter/2)²
- Triangle: 0.5 × Base × Height
- Trapezoid: 0.5 × (Base1 + Base2) × Height
- Sector: 0.5 × r² × θ (in radians)
- Parallelogram: Base × Height
Common Square Footage Conversions
- 1 square foot = 144 square inches
- 1 square yard = 9 square feet
- 1 square meter = 10.764 square feet
- 1 acre = 43,560 square feet
How to Use This Calculator
Select the shape that matches your surface from the dropdown menu. Enter the required dimensions and choose the appropriate unit of measurement. You can also specify a quantity for multiple identical areas and a price per square foot to estimate total material cost. Results update automatically and include area in square feet along with conversions to other common units.
Frequently Asked Questions
How do I calculate square footage of an irregularly shaped room?
For irregularly shaped rooms, divide the space into regular shapes (rectangles, triangles, etc.), calculate each area separately using this calculator, and add the results together. This is often called the "section method" and provides a close approximation of the total area.
How many square feet is a 12x12 room?
A room that is 12 feet by 12 feet has 144 square feet (12 × 12 = 144). This is a common bedroom size. To account for waste when buying flooring, add 5-10% to the total square footage.
How do I calculate cost per square foot?
To find the cost per square foot, divide the total cost by the total square footage. For example, if a 2,000 sq ft house costs $400,000, the cost per square foot is $200. Our calculator can compute the total cost when you enter the price per square foot.
What is the difference between square footage and square meters?
Square feet and square meters are both units of area. One square meter equals approximately 10.764 square feet. Most countries outside the US use square meters for real estate listings. Our calculator provides both measurements for easy comparison.
How much paint do I need per square foot?
One gallon of paint typically covers about 350-400 square feet of wall surface. For primer, coverage is usually 200-300 square feet per gallon. To estimate paint needs, calculate the wall square footage (wall height × wall length) and divide by the coverage rate.
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