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Square Footage Calculator

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Find the total square footage of a space - including irregular, L-shaped, or multi-room areas - by breaking it into rectangular sections and adding them together.

Square Footage Calculator

Live
SectionLength (ft)Width (ft)
Total square footage
168 sq ft

The formula

Total square footage = sum of (Length x Width) for each rectangular section
Example

An L-shaped room made of a 12x10 ft section and an 8x6 ft section: 120 + 48 = 168 sq ft total.

Step-by-step guide

  1. Break your space into rectangles - most rooms, even irregular ones, can be divided into two or more rectangular sections.
  2. Measure the length and width of each section in feet.
  3. Add more sections as needed using the button, and read the total.

Breaking down an irregular room

Most real rooms aren't perfect rectangles - an L-shaped living room, a kitchen with a bump-out, or a space with an alcove all need to be split into simpler rectangular pieces first. Sketch the room's outline, draw a line to divide it into rectangles, measure each piece separately, and enter them as separate sections here. For a triangular section (like a bay window nook), calculate its area separately (0.5 x base x height) and note it doesn't fit this rectangle-based tool directly - our Area Calculator handles triangles and other shapes.

Common mistakes

Double-counting an overlapping section when splitting an irregular shape into rectangles - each section should cover a distinct part of the total area with no overlap.
Measuring wall-to-wall including closets or nooks you don't intend to include (or excluding ones you do) - be clear about exactly what area you're trying to capture before measuring.

Frequently asked questions

Does real estate square footage work the same way?

Generally yes for the underlying math, but real estate listings often follow specific regional measurement standards about what counts as livable square footage (finished vs. unfinished space, garages, etc.) - this calculator just adds up the raw areas you enter.

How do I handle a room with a bay window or curved wall?

Approximate curved or angled sections as a rectangle close to their actual size, or use our Area Calculator for a triangle or circle segment specifically, then add that figure to your total from here.

Should I measure inside or outside the walls?

For interior projects like flooring or paint, measure the interior (usable) dimensions. For exterior or structural projects, outside wall-to-wall measurements are typically more relevant - use whichever matches your project's purpose.

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