Square Footage Calculator Formula

Understand the math behind the square footage calculator. Each variable explained with a worked example.

Use the Square Footage Calculator

Formulas Used

Square Footage

sqft = total_length * total_width

Square Meters

sqm = sqft * 0.0929

Acres

acres = sqft / 43560

Variables

VariableDescriptionDefault
length_ftLength (feet)(ft)15
length_inLength (inches)(in)0
width_ftWidth (feet)(ft)12
width_inWidth (inches)(in)0
total_lengthDerived value= length_ft + length_in / 12calculated
total_widthDerived value= width_ft + width_in / 12calculated

How It Works

Square Footage Formula

Area = Length × Width

Conversions

  • 1 sq ft = 0.0929 sq meters
  • 1 acre = 43,560 sq ft
  • 1 sq yard = 9 sq ft

    • Square footage is the standard unit for measuring floor area in the United States and is essential for estimating flooring, paint, and material costs. For irregularly shaped rooms, divide the space into rectangles, calculate each one separately, and add the results together.

    Worked Example

    A room that is 15 ft × 12 ft.

    length_ft = 15length_in = 0width_ft = 12width_in = 0
    1. 01Area = 15 × 12 = 180 sq ft
    2. 02In square meters = 180 × 0.0929 = 16.7 sq m

    Frequently Asked Questions

    How do I measure an oddly shaped room?

    Break it into rectangles, calculate each area separately, then add them together.

    How many square feet is a standard room?

    A typical bedroom is 120-200 sq ft (10x12 to 12x16), a master bedroom is 200-350 sq ft, a living room is 200-400 sq ft, and a single-car garage is about 200 sq ft. A standard US home averages around 2,300 sq ft total.

    How do I convert square footage to square yards?

    Divide the square footage by 9, since one square yard equals 9 square feet. This conversion is commonly needed when buying carpet, which is often priced per square yard. For example, 180 sq ft equals 20 sq yards.

    Learn More

    Guide

    How to Calculate Flooring Area and Material Quantities

    Learn how to measure rooms and calculate flooring material needed for tile, hardwood, carpet, and laminate. Covers irregular rooms, waste factors, and cost estimation.

    Ready to run the numbers?

    Open Square Footage Calculator