Square Foot

What is a Square Foot?

A square foot is a unit of area measurement equal to a square that measures 12 inches (1 foot) on each side. It's the standard unit for measuring floor area, wall surfaces, and many construction materials in the United States.

Square footage is fundamental to construction estimating, pricing, and material ordering.

Common Square Foot Applications

Pricing Services

Many contractors price work per square foot:

• Flooring installation: $3-$12 per square foot
• Interior painting: $1-$4 per square foot
• Roofing: $3-$8 per square foot
• Drywall installation: $1-$3 per square foot

Material Ordering

Many materials are sold by square foot coverage:

• Carpet and flooring materials
• Paint (covers ~350-400 sq ft per gallon)
• Insulation batts and rolls
• Roofing shingles and underlayment

Building Measurements

• Total home size (living space)
• Room dimensions for planning
• Property lot sizes (often in square feet for smaller lots)

Calculating Square Footage

Basic Formula

Length (in feet) × Width (in feet) = Square Feet

Examples

• Room: 12 ft × 10 ft = 120 square feet
• House: 40 ft × 60 ft = 2,400 square feet
• Wall: 8 ft high × 12 ft wide = 96 square feet

Irregular Shapes

Break complex areas into rectangles, calculate each section, then add together.

Measurement Tips

For Flooring

• Measure length and width of each room
• Add 5-10% extra for waste and cuts
• Subtract for permanent fixtures (kitchen islands, built-ins)

For Painting

• Calculate wall area: (Length + Width) × 2 × Height
• Subtract for windows and doors
• Don't forget ceilings if painting

For Roofing

• Measure roof sections, not floor area
• Account for pitch/slope increase
• Add extra for waste and starter courses

Converting Square Foot Measurements

Square Feet to Square Yards: Divide by 9

• 1 square yard = 9 square feet
• 180 sq ft = 20 square yards

Square Feet to Square Inches: Multiply by 144

• 1 square foot = 144 square inches

Acres to Square Feet: Multiply by 43,560

• 1 acre = 43,560 square feet

Industry Standards

Residential Construction

• Small homes: 1,000-1,500 sq ft
• Average homes: 1,500-2,500 sq ft
• Large homes: 2,500+ sq ft

Commercial Spaces

• Small office: 1,000-5,000 sq ft
• Retail stores: 2,000-10,000+ sq ft
• Warehouses: 10,000-100,000+ sq ft

Pricing Considerations

Economy of Scale: Larger areas typically have lower per-square-foot pricing.

Complexity Factors: Intricate layouts, multiple rooms, or obstacles increase per-square-foot costs.

Access Issues: Difficult-to-reach areas command higher per-square-foot rates.

Quality Levels: Premium materials and finishes increase per-square-foot pricing significantly.

Common Mistakes

Incorrect Measurements: Always double-check calculations and measurements.

Forgetting Waste: Not adding appropriate waste factors for cuts and mistakes.

Omitting Areas: Missing closets, hallways, or irregular spaces in calculations.

Using Floor Area for Walls: Wall area calculations require different measurements than floor area.