Square Footage Calculator

Estimate the square footage of a lot, house, or surface. For complex spaces, use the "Add Shape" buttons to section the area into simple rectangles, triangles, and circles to automatically sum up the total square footage and cost.

Rectangle

Length (ft)

Width (ft)

Quantity

Rectangle Border

Outer Length (ft)

Outer Width (ft)

Inner Length (ft)

Inner Width (ft)

Quantity

Circle

Radius (ft)

Quantity

Ring

Outer Radius (ft)

Inner Radius (ft)

Quantity

Triangle with Edge Lengths

Edge 1 (a) (ft)

Edge 2 (b) (ft)

Edge 3 (c) (ft)

Quantity

Triangle with Base & Height

Base (ft)

Height (ft)

Quantity

Trapezoid

Base A (top) (ft)

Base B (bottom) (ft)

Height (ft)

Quantity

Sector

Radius (ft)

Angle (degrees)

Quantity

Parallelogram

Base (ft)

Height (ft)

Quantity

Grand Total
Sum of all calculated shapes

0.00

Square Feet (sq ft)

Square Meters0.00 m²

Square Yards0.00 yd²

Price per sq ft $

How to Measure Complex Spaces

Rarely are rooms perfectly rectangular. If you are trying to calculate the area of an L-shaped room or a yard with curved edges, the best strategy is to visually "section" the space into primitive geometric shapes.

For example, an L-shaped room can be split into two separate rectangles. Calculate the length and width of the first rectangle, and then the length and width of the second. In our calculator above, you can simply click "Add Rectangle" to input the second shape. The calculator will automatically add their areas together to give you the total square footage needed for your flooring or painting project.

All 9 Area Formulas

Our calculator instantly processes the math for any combination of the following 9 standard real-estate and geometry shapes:

RectangleL × W
Rectangle Border(L₁×W₁) - (L₂×W₂)
Circleπ × R²
Ringπ × (R₁² - R₂²)
Triangle (Base/Height)(B × H) / 2
Triangle (3 Edges)Heron's Formula
Trapezoid((A + B) / 2) × H
Sector(θ / 360) × π × R²
ParallelogramB × H

Unit Conversions

While Square Feet (sq ft) is the standard in the US, contractors or material suppliers might quote you in square yards or square meters.

1 Square Yard = 9 Square Feet

1 Square Meter ≈ 10.764 Square Feet

1 Acre = 43,560 Square Feet

Calculating Cost Per Square Foot

Painting a House

When painting a house, professional house painters often base price quotations on the square footage of a property. Alternatively, even if a person plans to paint their house themselves, measuring square footage can yield accurate estimates of the amount of paint required. Depending on the surface being painted (wood, metal, plastic, etc.), primer may be necessary. Estimated coverage amounts can range anywhere between 200-400 square feet per gallon.

Flooring Costs

There are a number of materials commonly used for flooring, including wood, laminate, and tile. Flooring costs can vary significantly depending on the quality and choice of materials:

Wood Flooring: Includes hardwood, engineered wood, and bamboo. Highly durable and versatile, but may require sanding and refinishing over time.
Laminate Flooring: Typically made with plywood or fiberboard with a plastic laminate top layer. Less costly, highly durable, and difficult to scratch or dent.
Tile Flooring: Includes ceramic, glass, and natural stone. The many options allow a person to choose a cost and style that fits their needs, though installation can be more difficult.

Building a Home

The cost of building a home varies largely based on materials, foundation type, roof pitch, and many other characteristics not directly related to size. Because of this, cost per square foot for building is often estimated based on averages. Having a reference can help a prospective owner decide whether or not to include extravagant features like elegant master baths or curved staircases.