How to Calculate Siding Squares

Siding Squares Calculator

Use this calculator to estimate the number of siding squares needed for your project. A "siding square" is a standard unit of measurement in the siding industry, equivalent to 100 square feet of material.

Wall Dimensions

ft

ft

Gable End Dimensions (Triangular Sections)

ft

ft

Openings (Windows & Doors)

ft

ft



ft

ft

Waste Factor

%

Understanding Siding Squares

When planning a siding project, one of the first and most crucial steps is accurately determining how much material you'll need. Siding is typically sold in "squares," with one square covering 100 square feet. This unit simplifies ordering and pricing for contractors and suppliers.

How to Measure for Siding

1. Measure Rectangular Walls: For each rectangular wall section, measure its length and height. Multiply these two numbers to get the square footage. If your house has a consistent wall height, you can sum the lengths of all rectangular walls and multiply by the average height.
2. Measure Gable Ends: Gable ends are the triangular sections at the top of walls, typically found on houses with pitched roofs. To calculate the area of a gable, measure its base (the width of the wall at the eaves) and its vertical height (from the base to the peak). The formula for a triangle's area is (0.5 * Base * Height).
3. Measure Openings (Windows & Doors): You'll need to subtract the area of all windows and doors from your total wall area, as these sections won't be covered by siding. Measure the width and height of each window and door, then multiply to find its area. Sum all these areas.
4. Calculate Gross Area: Add up the square footage of all your rectangular walls and gable ends. This is your total gross area.
5. Calculate Net Area: Subtract the total area of all windows and doors from your gross area. This gives you the net square footage that actually needs siding.
6. Apply a Waste Factor: It's essential to account for waste due to cuts, mistakes, damaged pieces, and future repairs. A typical waste factor ranges from 5% to 15%, depending on the complexity of the house design and the type of siding. Multiply your net area by (1 + waste factor percentage / 100). For example, for a 10% waste factor, multiply by 1.10.
7. Convert to Siding Squares: Divide your final square footage (including waste) by 100 to get the number of siding squares.

Example Calculation

Let's say you have a house with the following dimensions:

• Total Linear Feet of Walls: 140 ft
• Average Wall Height: 10 ft
• Number of Gable Ends: 2
• Average Gable Base Width: 30 ft
• Average Gable Height: 5 ft
• Number of Windows: 10 (each 3 ft wide x 4 ft high)
• Number of Doors: 2 (each 3 ft wide x 7 ft high)
• Waste Factor: 10%

1. Rectangular Wall Area: 140 ft * 10 ft = 1400 sq ft
2. Gable End Area: 2 * (0.5 * 30 ft * 5 ft) = 2 * 75 sq ft = 150 sq ft
3. Total Gross Area: 1400 sq ft + 150 sq ft = 1550 sq ft
4. Window Area: 10 * (3 ft * 4 ft) = 10 * 12 sq ft = 120 sq ft
5. Door Area: 2 * (3 ft * 7 ft) = 2 * 21 sq ft = 42 sq ft
6. Total Opening Area: 120 sq ft + 42 sq ft = 162 sq ft
7. Net Siding Area: 1550 sq ft – 162 sq ft = 1388 sq ft
8. Area with Waste: 1388 sq ft * (1 + 10/100) = 1388 sq ft * 1.10 = 1526.8 sq ft
9. Siding Squares: 1526.8 sq ft / 100 = 15.27 squares (rounded)

Using the calculator above will help you quickly get an accurate estimate for your project.

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Estimated Siding Needed:

" + "" + sidingSquares.toFixed(2) + " Siding Squares" + "(" + areaWithWaste.toFixed(2) + " total square feet including waste)"; }