Square Footage Calculator

About the Square Footage Calculator

Square footage is the universal language of real estate, construction, and interior design. Whether you're buying flooring, calculating paint coverage, or simply understanding a property listing, knowing the area in square feet is essential.

The Basic Formula

Area (sq ft) = Length (ft) × Width (ft). For a room that is 15 feet long and 12 feet wide: 15 × 12 = 180 sq ft.

Measuring Irregular Rooms

Most rooms aren't perfect rectangles. Break L-shaped or T-shaped rooms into smaller rectangles, calculate each section separately, then add them together. This tool allows you to enter multiple areas and totals them automatically.

Common Uses

Flooring: Add 10% overage to your square footage for cuts and waste. A 180 sq ft room needs about 198 sq ft of material purchased.

Paint: One gallon typically covers 350–400 sq ft per coat. A 180 sq ft room with 8-foot ceilings has approximately 350 sq ft of wall area (perimeter × height minus doors and windows).

Real estate: Price per square foot = Sale Price ÷ Square Footage. This metric lets you compare properties of different sizes objectively.

HVAC sizing: A general rule of thumb is 20 BTU per square foot. A 1,800 sq ft home needs roughly 36,000 BTU (3-ton) air conditioning.

Square Feet to Square Meters

1 square foot = 0.0929 square meters. Multiply square feet by 0.0929 to convert to sq m, or divide sq m by 0.0929 to get sq ft.

Average room sizes: Bedroom: 120–200 sq ft | Living room: 200–400 sq ft | Kitchen: 100–200 sq ft | Master bedroom: 200–300 sq ft | Studio apartment: 300–600 sq ft.