Square Footage Calculator

Calculate rectangular floor or surface area and estimate material coverage.

InputsChange a value to recalculate instantly

Length

Width

ResultUpdates as you type

Area300 ft²

Perimeter70 ft

With 10% waste330 ft²

How it worksTransparent math

FormulaA=length×width

Calculates rectangular surface area and adds a simple material-waste allowance.

Result breakdownSee the important numbers together

1Area300 ft²

2Perimeter70 ft

3With 10% waste330 ft²

λ DooMathWork with this calculation

Local · deterministic · optional

auto_awesome

Quick mathNatural-language-style shortcuts for deterministic arithmetic.

Calculator guide

How to use the Square Footage Calculator

Calculate rectangular floor or surface area and estimate material coverage.

01Set inputsChoose values, units and assumptions.

02Apply the modelArea = length × width

03Read the resultCheck the output against the assumptions before using it.

menu_book

Calculate rectangular floor or surface area and estimate material coverage.

functions

Area = length × width

fact_check

Review the inputs, units and assumptions before using the result for a real decision.