Square Footage Calculator
Calculate square footage for rectangular, circular, triangular, and trapezoidal areas. Add multiple rooms to get a total.
How It Works
This calculator computes area based on the shape you select, then converts to multiple units.
Rectangle: Area = Length × Width
Circle: Area = π × Radius²
Triangle: Area = Base × Height ÷ 2
Trapezoid: Area = (Side A + Side B) ÷ 2 × Height
Use the "Add to Room List" button to measure multiple areas and get a combined total, perfect for irregular floor plans or multi-room projects.
Frequently Asked Questions
How do I calculate square footage?
For a rectangle, multiply the length by the width in feet. For example, a 12 ft x 10 ft room is 120 square feet. For other shapes, use the appropriate formula: circles use pi x radius squared, triangles use base x height / 2, and trapezoids use (side A + side B) / 2 x height.
How many square feet are in an acre?
There are 43,560 square feet in one acre. To convert square feet to acres, divide the total square feet by 43,560.
How do I convert square feet to square meters?
Divide the square footage by 10.764 to get square meters. For example, 500 sq ft / 10.764 = 46.45 square meters.
How do I measure square footage of an irregular room?
Break the room into smaller regular shapes (rectangles, triangles, etc.), calculate each area separately, then add them together. Use the room-by-room feature in this calculator to track each section.
What is the difference between square feet and linear feet?
Linear feet is a one-dimensional measurement of length. Square feet is a two-dimensional measurement of area (length x width). You need square feet for flooring, paint, and material coverage calculations.