Does square footage include walls?

No. Square footage for flooring is the 'Net Internal Area'—the floor space you can walk on. However, real estate listings ('Gross Internal Area') often measure from the outside of the walls, making the house seem slightly bigger.

How do I measure a room with a closet?

Treat the closet as a separate small rectangle. Measure its length and width, calculate the area, and add it to the main room's total. Don't forget the doorway transition area!

What is the standard waste factor?

10% is the industry standard for standard cuts. 15% is safer for tile (due to breakage). 20% is recommended if you are laying the floor diagonally, as the off-cuts are often unusable.

Measuring Up: The Ultimate Square Footage Guide

Whether you are buying carpet, hardwood, or just checking your home's value, Square Footage is the most important number in real estate. Getting it wrong can cost you hundreds of dollars in wasted material.

Renovating?

Calculate total area, subtract islands, and add waste factor automatically.

Open SQ FT Calculator

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The Basics: Area = Length x Width

Square footage is a measure of Area.
If you have a room that is a perfect rectangle, the math is simple.

Room Length: 12 feet
Room Width: 10 feet
Area: 12 x 10 = 120 Sq Ft.

How to Handle Complex Rooms

Most modern rooms aren't perfect boxes. They have closets, nooks, alcoves, and bay windows. The strategy here is Divide and Conquer.

1. The L-Shape

Imagine an L-shaped living room combined with a dining nook.
Don't try to measure the weird 6-sided shape.
Draw a line to split it into Rectangle A and Rectangle B.
Calculate both separately and add them up.

2. Subtracting Obstacles (Kitchen Islands)

If you are tiling a kitchen, you don't tile under the fixed island or cabinets.
1. Calculate the TOTAL room area (wall to wall).
2. Calculate the ISLAND area.
3. Subtract the island from the total.

The "Warning": Waste Factors

Never order exactly the square footage you measured.
You will need to cut pieces to fit corners, around pipes, and door jambs. Once you cut a plank, the leftover piece is often too small to use elsewhere. This is called "waste."

Material	Waste Factor	Why?
Carpet (Roll)	0% - 10%	Rolls are fixed width (12'). You pay for the whole width even if your room is 10' wide.
Laminate / Vinyl	5% - 10%	Easy to cut, minimal breakage.
Hardwood	10%	Natural defects (knots) may need to be cut out.
Ceramic Tile	15%	Tiles break easily when cut.
Diagonal Layout	+20%	Diagonal cuts produce triangles that are often unusable.

Calculating Total Cost

Flooring is priced per square foot, but don't forget the extras.

Underlayment: The foam padding under the floor (approx $0.50/sq ft).
Baseboards/Trim: Sold by the Linear Foot (length), not square foot.
Installation: Pros charge $2-$5 per sq ft for labor.

Example Comparison

Room: 200 Sq Ft.
Material: $4.00/sq ft.

Wrong Way: 200 x $4 = $800.

Right Way:

Add 10% Waste: 200 + 20 = 220 Sq Ft.
Material Cost: 220 x $4 = $880.
Add Underlayment (220 x $0.50): +$110.
Real Total: $990.

Conclusion

Square footage is more than just measuring measurement tape. It's about planning for the real world (waste, weird corners, and roll widths). Using a calculator helps you visualize the waste and budget accurately so you don't get stuck with a half-finished floor and an empty wallet.