Siding Calculator: How Much Siding Do I Need?
Don’t let your siding project blindside you
How much siding you need is based on square footage totals.
Measure each wall individually.
Triangular sections require a different but simple formula.
Remember to subtract doors, windows, and chimneys.
Homes require siding, but how much do you need? Calculations aren’t too difficult, but accuracy is paramount. When determining how much siding you need, remember the saying: “Measure twice, cut once.” Use the siding calculator below to determine the total square feet of siding you need.
How Much Siding Needed for an Average Home
You can calculate the area of your home fairly easily—even with a sloped roof. While siding can be sold in squares (1 square is 100 square feet), it’s easiest to calculate in square foot totals. Refer to the table below to estimate how much siding you’ll need to cover your home.
| Type of Area | How to Measure Square Footage | Notes |
|---|---|---|
| Rectangular walls | Base x height | Basic walls |
| Gables (triangular) | (Base x height) / 2 | Triangular section |
| Soffits | Width x length | Under-eave surface |
| Windows and doors | Width x height | Subtract from totals above |
How to Calculate Siding Requirements
Formulating how much siding is required is simple once you have your measurements. Use the formula below to determine the total amount of siding required:
Siding Required (in square feet) = Rectangular walls (length x height) + angled section (length x height of the angled section / 2) + soffit (length x width) - window and door space (total square footage)
How to Measure for Siding
If your home has a flat roof, you’ll only need to measure the walls in one piece, adding them up to a grand total. However, if your roof is angled, you need to break up each wall into two sections: the rectangular bottom and the triangular top. Measure and calculate these two pieces separately, then add them together later.
How to Measure Rectangular Walls
Finding the square footage of a rectangular wall is simple. Measure the base of the wall, then measure the height, then multiply them for the result.
How to Measure Angled or Pitched Roof Sections
Not many homes have flat roofs, so you’ll need to measure the angled part of your wall separately from the rectangular section. Measure the base (width) of the wall and the height from the base to the highest point of the roof. Multiply these together, then divide by two to get the square footage of the triangular section of the wall.
How to Measure Soffits
Soffits are the panels that cover the underside of your eaves and are commonly installed in sizes ranging from 8 inches to 20 inches wide. The length of the roof determines the length of the soffit, and calculations are the same ones you’d use to measure rectangular walls (length times width).
How to Factor in Doors and Windows
You won’t be adding siding to your doors and windows. Use the same calculations above for rectangular doors and windows (base times height). Keep the numbers handy, as you’ll subtract them from the wall totals above. Remember that many homes use the same windows throughout, so you probably don’t need to measure each one individually.
Who to Hire to Measure Siding
Siding isn’t an inexpensive project, and the materials can cost thousands of dollars. A local siding pro can get accurate measurements if you don’t want to risk making costly mistakes handling the project on your own. Ask a siding contractor if this process is included in the project fee if you use them to replace your siding.
Frequently Asked Questions
No, you don’t need to use the same siding around the entire home. Using different siding for different walls can actually increase the soft value of your home. Many homeowners opt to add vinyl siding on the sides of their home not facing the street, opting for higher-end siding materials like stone or wood for the front of the house. Stone veneer siding can be a cost-effective option for homeowners who like the appearance of stone, but not the cost.
The cheapest and most inexpensive way to side a house is to use vinyl. Vinyl is very low-cost but may not last as long as natural materials or metal. However, it often lasts the same length of time the owners plan on living in the home (about 20 to 40 years). Certain types of vinyl siding, like vinyl shake, can be as low as $3 per square foot, but ask a siding pro if the lowest-cost option is the best material for your particular home.
On average, siding lasts between 20 and 40 years. Most of the common materials used in siding—vinyl and wood siding—can last around 30 years if taken care of. Upscale options like stone, brick, and aluminum can last up to 100 years or more but will cost much more to purchase and aren’t as simple to install.
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