RightSizeTools Practical sizing calculators
Geometry Basics

Rectangle Area Calculator

Use this for rectangular rooms, walls, panels, slabs, yards, and project areas.

Last updated: May 2026

Unit system Switch between U.S. customary and metric units. Your choice is remembered on other calculators.

Rectangle dimensions

Enter the length and width in the units you know. The result will show both square feet and square meters.

Visual guide

Which measurement goes where?

Use the long horizontal side as length and the side-to-side dimension as width.

ft
ft
Advanced settings
%

Buying and sizing notes

How to use this estimate

What this includes

  • The required inputs shown on this page
  • common planning assumptions
  • optional advanced adjustments where provided

What it does not include

  • site-specific professional design
  • local code approval
  • manufacturer-specific requirements
  • installation quality

Common mistakes

  • Leaving a required input at the default when your situation is different
  • ignoring product labels or ratings
  • treating the estimate as an exact final answer

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