Square Footage Calculator
Calculate the area of a room or house footprint in square feet, yards and metres.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Calculate area for one rectangle or several identical rooms. Enter length and width in feet; the room count multiplies the same dimensions. For rooms with different sizes or irregular shapes, calculate each area separately and add the results.
Worked example
calculated with the default values below
Length 20 ft · Width 15 ft · Number of identical rooms 1 · Price per square foot (optional) 0 $ Total area 300.00 sq ft · Total area 33.33 sq yd · Total area 27.87 m² · Total area 0.0069 acres · Value at that price per sq ft 0 $
General background references
Disclaimer
These calculators provide planning estimates only. Building codes, wiring regulations and safety requirements differ by country and change over time, and nothing here replaces a licensed professional or a permit. For structural, electrical or gas work, follow local code and have the installation inspected.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
A = L × W × n; sq yd = A÷9; m² = A×0.09290304; acres = A÷43560
- L
- Length (ft)
- W
- Width (ft)
- n
- Number of rooms
Total value = A × price per sq ft, when a price is entered.
Frequently asked questions
How does the room count affect the area?
Calculate area for one rectangle or several identical rooms. Enter length and width in feet; the room count multiplies the same dimensions. For rooms with different sizes or irregular shapes, calculate each area separately and add the results.