Home & Construction

Square Footage Calculator

Area in square feet and square meters.

The simplest calculator here: enter any rectangle's length and width in feet and get the area in square feet and square meters. Use it for rooms, gardens, plots, or comparing listings. It is the building block behind our paint, flooring, and tile calculators.

Introduction

Square footage is the area of a surface in square feet — the single number behind real-estate listings, flooring orders, paint estimates, and rental prices. For a rectangle, it is length times width, both in feet: a 12 by 15 foot room is 180 sq ft. That is the entire core concept; everything else is handling shapes that are not rectangles. The number matters because it is the common currency of space: landlords price by it, contractors bid by it, and building codes regulate by it.

For non-rectangular spaces, decompose into shapes you know. L-shaped rooms become two rectangles added together. Triangles are half the base times the height. Circles are pi times the radius squared (a 6-foot-radius patio is about 113 sq ft). Trapezoids — common in bay windows and attics — are the average of the two parallel sides times the distance between them. Measure in feet and inches, convert inches to decimal feet (6 inches = 0.5 ft) before multiplying, and keep one decimal place in the answer; false precision helps nobody.

To convert square feet to square meters, multiply by 0.09290304 — a 1,000 sq ft apartment is 92.9 m². For quick mental math, 10 sq ft is roughly 1 m² (actually 0.93 m²), close enough for conversation but not for ordering materials. This calculator handles rectangles, circles, triangles, and composite shapes.

How it's calculated

Square feet = length × width in feet. Square meters = square feet × 0.09290304.

Worked examples

A rectangular room, 18 x 24 feet

Multiply: 18 x 24 = 432 sq ft. In square meters: 432 x 0.09290304 = 40.13, or about 40.1 m². For flooring with 10 percent waste, order 432 x 1.10 = 475.2, or 476 sq ft of material. The room is also a useful benchmark: 432 sq ft is a generous master bedroom or a small studio apartment, and at a $2/sq ft flooring cost the material bill is about $864 before waste — the kind of instant budget the square footage unlocks.

A circular patio with 6 ft radius

Area = pi x r² = 3.14159 x 36 = 113.097, or about 113.1 sq ft. For pavers with 10 percent waste: 113.1 x 1.10 = 124.4 sq ft of pavers. If the patio were measured by diameter instead (12 ft across), halve first: radius 6 ft, same result — a common error is squaring the diameter, which quadruples the answer to 452 sq ft. When in doubt, sketch the shape and label the measurements; five seconds of drawing prevents the most expensive arithmetic mistakes in home improvement.

Frequently asked questions

How do you calculate square footage?

Multiply length by width. A room that is 10 ft long and 12 ft wide has an area of 120 square feet.

How do I convert square feet to square meters?

Multiply square feet by 0.0929. So 120 sq ft equals about 11.15 m² — our calculator shows both units side by side.

Is square footage the same as cubic feet?

No — square footage measures area (length × width). Cubic feet measure volume (length × width × height), which is a different number entirely.

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