Square Footage Calculator
Calculate square footage for rectangles, circles, triangles, and L-shapes.
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💡 Did you know? Saving this calculation connects it to our Project Planner, allowing you to bundle multiple estimates (concrete, paint, tile, etc.) into a unified shopping list with shared measurements.
Frequently Asked Questions
How to measure square footage of a room?
To measure the square footage of a standard rectangular room, use a tape measure to find the length and width of the floor in feet. Multiply those two numbers together (Length × Width) to calculate the total square feet. For rooms with alcoves, closets, or L-shapes, divide the floor space into individual rectangular sections, calculate the square footage of each section separately, and sum them together. If you are planning flooring or paint, use our online Square Footage Calculator to easily sum multiple areas and add a 10% safety waste factor.
What's the square footage of a 12x12 room?
A 12x12 room is 144 sq ft. This is wall-to-wall floor area — wall paint needs perimeter x ceiling height.
How many square feet in an acre?
43,560 square feet = 1 acre. A 209 ft x 209 ft square is roughly one acre.