Square Footage Calculator

How Square Footage Is Calculated

Square footage is the area of a space measured in square feet. For a rectangle, the formula is:

Square Feet = Length (ft) x Width (ft) $$A=L\times W$$

For multiple rooms, calculate each room separately and sum the results:

$$A_{\text{total}}=\sum _{i=1}^n{L}_i\times W_i$$

Variable Definitions

Length: The longer dimension of a rectangular space, measured in feet. Measure from wall to wall at floor level, not along baseboards. Common mistake: measuring diagonally instead of along the wall.

Width: The shorter dimension of a rectangular space, measured in feet. In a perfectly square room, length and width are equal.

Cost per square foot: The price of materials or services per square foot. Flooring typically ranges from $2 to $15 per square foot depending on material. Painting services average $1.50 to $4 per square foot.

Worked Example

You have three rooms to floor:

1. Living room: 15 ft x 12 ft = 180 sq ft
2. Bedroom: 12 ft x 10 ft = 120 sq ft
3. Kitchen: 10 ft x 8 ft = 80 sq ft

Total = 180 + 120 + 80 = 380 sq ft

In square meters: 380 / 10.764 = 35.30 sq m

At $6.50 per square foot for laminate flooring: 380 x $6.50 = $2,470.00

Edge Cases and Advanced Scenarios

Non-rectangular rooms: For triangular areas, use (base x height) / 2. For circular areas, use pi x radius squared. Break irregular shapes into simple geometric shapes, calculate each, and sum them. Use the "Add Room" feature to enter each sub-shape as a separate row.

Closets and alcoves: Measure closets and alcoves as separate rectangles and add them. Many people forget to include closet space in their calculations, which leads to ordering too little material. A standard closet adds 6-12 square feet.

What to Do with Your Result

• Add 10-15% waste factor for flooring, tile, or carpet purchases before ordering materials.
• Get quotes from at least three contractors using your exact square footage to compare prices accurately.
• Check local building codes — some renovations require permits above certain square footage thresholds.
• Use the cost estimate to set a realistic project budget before visiting the home improvement store.