Square Footage Calculator

Calculate the square footage of various shapes including rectangles, circles, triangles, and more. Our free online square footage calculator helps with flooring, painting, and construction projects.

Square Footage Calculator

This calculator estimates the square footage of a lot, house, or other surfaces in several common shapes. If the surface is complex in shape, it may be possible to section the surface into simple shapes and add their square footages together.

Enter Dimensions

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Square Footage Calculator Guide

What is a Square Footage Calculator?

A square footage calculator is a tool that helps you determine the area of a space, surface, or object in square feet (or other square units). It can calculate the area of various shapes like rectangles, circles, triangles, and more complex geometries.

Calculating square footage is essential for many home improvement, construction, and design projects. It helps determine how much material to purchase, estimate costs, and plan layouts effectively.

Using a square footage calculator saves time, reduces errors, minimizes waste, and helps ensure you purchase the right amount of materials for your project.

How to Use This Calculator

Our square footage calculator supports multiple shapes and is designed to be easy to use:

Step-by-Step Guide

  1. Select the shape that best matches the area you want to calculate.
  2. Enter the required measurements (length, width, diameter, etc.) in your preferred units.
  3. Specify the quantity if you have multiple identical areas.
  4. Optionally, enter a price per square foot for cost estimation.
  5. Click the 'Calculate' button to see the results.

Area Calculation Formulas

Different shapes require different formulas to calculate their area. Here are the formulas used in our calculator:

Rectangle

$$Area = Length \ imes Width$$

The area of a rectangle is simply the product of its length and width.

Rectangle Border

$$Area = (Length \ imes Width) - ((Length - 2 \ imes BorderWidth) \ imes (Width - 2 \ imes BorderWidth))$$

The area of a rectangular border is calculated by subtracting the inner rectangle's area from the outer rectangle's area.

Circle

$$Area = \pi \ imes Radius^2 = \pi \ imes (\ rac{Diameter}{2})^2$$

The area of a circle is calculated using the formula pi times the radius squared. The radius is half the diameter.

Ring

$$Area = \pi \ imes (OuterRadius^2 - InnerRadius^2) = \pi \ imes (OuterRadius^2 - (OuterRadius - BorderWidth)^2)$$

The area of a ring (annulus) is the difference between the areas of the outer circle and the inner circle.

Triangle with Edge Lengths

$$Area = \sqrt{s(s-a)(s-b)(s-c)}$$

Where s is the semi-perimeter:

$$s = \ rac{a + b + c}{2}$$

The area of a triangle using all three side lengths is calculated using Heron's formula.

Triangle with Base & Height

$$Area = \ rac{Base \ imes Height}{2}$$

The area of a triangle is half the product of its base and height.

Trapezoid

$$Area = \ rac{(Base1 + Base2) \ imes Height}{2}$$

The area of a trapezoid is half the product of its height and the sum of its parallel sides.

Common Applications

Square footage calculations are used in many applications, including:

Flooring Installation

Calculate how much flooring material (tile, hardwood, carpet, etc.) you need for a room or building.

Painting Projects

Determine how much paint you need for walls, ceilings, or other surfaces.

Roofing Projects

Estimate the amount of roofing material needed based on the roof's dimensions.

Landscaping

Calculate areas for lawn seeding, mulching, paving, or other landscaping materials.

Practical Tips & Best Practices

Accurate Measurements

Always measure twice to ensure accuracy. Small measurement errors can lead to significant area calculation errors.

Allow for Extra Material

Add 5-10% extra to your calculated area to account for cuts, waste, and mistakes, especially for flooring and tiling projects.

Handling Irregular Shapes

For irregular shapes, break the area into simpler geometric shapes, calculate each one separately, and add them together.

Complex Spaces

For rooms with alcoves, bay windows, or other features, measure the main area and add or subtract the additional features accordingly.

Frequently Asked Questions

What is the difference between square feet and cubic feet?

Square feet measures area (length × width) and is used for surfaces like floors and walls. Cubic feet measures volume (length × width × height) and is used for three-dimensional spaces.

How do I calculate square footage of an irregular shape?

Break the irregular shape into standard geometric shapes (rectangles, triangles, etc.), calculate the area of each part, and add them together for the total square footage.

Should I include closets and other small areas when calculating room square footage?

Yes, if you're buying flooring or calculating total living space, include all areas that will be covered, including closets, pantries, and other small spaces.

How much extra material should I purchase for a flooring project?

It's generally recommended to purchase 5-10% extra material to account for cuts, waste, and potential future repairs. For complex patterns or diagonal installations, consider adding 15%.

How do I convert between different area units?

Our calculator provides automatic conversions, but as a reference: 1 square meter = 10.764 square feet, 1 square foot = 0.111 square yards, and 1 acre = 43,560 square feet.