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Siding Calculator

Created by Bogna Szyk
Reviewed by Dominik Czernia, PhD and Steven Wooding
Last updated: May 20, 2024

This siding calculator is a perfect tool if you're planning to cover the walls or gables of your house with panels – be it wooden, metal, or vinyl siding. In the article below, you will find all the information necessary for such a construction project. We'll start you off with a short instruction on how to measure for siding accurately and determine how much siding you need. We'll also help you estimate the siding cost you will bear. Last but not least, we'll elaborate on the most common types of siding and help you choose the most appropriate type for your house.

How to measure for siding?

Before you get in your car and make a trip to Home Depot, you should consider how much siding you need. As siding is placed on the walls and gables of a house, the whole calculation process boils down to determining the square footage of the area you're going to cover: we teach you how to do that in Omni's square footage calculator. Naturally, it's a good idea to subtract the area of any openings (i.e., doors and windows) – after all, you don't want to cover them with siding panels!

Of course, you don't have to perform all calculations by hand; our siding calculator is at your disposal! All you need to do is grab a measuring tape or a rangefinder and measure the following:

  1. The dimensions of your wall and/or gable. In both cases, the most important dimensions are height and width.

  2. The dimensions of any openings – doors and windows. You don't need to do this, as our siding calculator assumes the most popular opening size by default; nevertheless, if the openings in your house are unconventional, you might want to change these dimensions.

  3. The number of openings. You don't need anything complicated here – simply count them and input the numbers into our siding calculator.

The procedure would be the same if you wanted to paint your house: if this is what you need, visit our paint calculator!

How much siding do I need?

Once you're done with all the measuring, you can relax – our siding calculator takes it from there. It uses the following formula to estimate the total area of siding:

Atot=(B×H(n1×A1)(n2×A2))×(1+w),\footnotesize \begin{split} A_{\mathrm{tot}}&= \Big(B\times H - (n_1\times A_1)\\ &\quad- (n_2\times A_2)\Big)\times(1+w), \end{split}


  • BB — Width of the wall;
  • HH — Height of the wall;
  • n1n_1 — Number of doors;
  • A1A_1 — Area of a single door opening;
  • n2n_2 — Number of windows;
  • A2A_2 — Area of a single window opening;
  • ww — Waste factor; and
  • AtotA_\mathrm{tot} — Total area of siding needed.

The waste factor accounts for any waste of material that occurs due to trimming or cutoffs. It is expressed as a percentage of the net wall area. A typical value could be 5%5\%-10%10\%; the more complicated the project is, the more waste you are likely to generate.

If you're estimating the siding area for a gable, divide the value B×HB \times H by a factor of two – this will account for the triangular shape of the roof.

How much does siding cost?

To estimate the siding cost, you will need additional information – the unit price of siding. It is expressed as the price per unit area, for example, $/ft2\text{\textdollar}/\mathrm{ft^2} or /m2\text{€}/\mathrm{m^2}.

Siding is typically sold in squares – units of area measuring 100100 square feet. For example, an average box of vinyl contains two squares of material, which amounts to 200200 square feet. For this reason, it's important to always pay special attention to how much material is sold in one package and identify the unit price rather than the price per one square.

Once you know the unit price, you're one step away from knowing how much the siding is going to cost! All you have to do is multiply it by the total area:

price=unit price×area\footnotesize \mathrm{price} = \mathrm{unit\ price}\times\mathrm{area}

The last thing to do is write down the total cost of your project and head straight to a store with construction materials!

Estimate the siding cost: an example

Let's try to estimate the cost of siding for a simple rectangular wall with three openings: two windows and an entrance door.

  1. Determine the width and height of the wall. Let's assume H=8 mH = 8\ \mathrm{m} and B=14 mB = 14\ \mathrm{m}.

🙋 If you think in imperial rather than in metric, you can use our handy length converter to find how many feet those measurements are!

  1. Choose whether you want to measure the dimensions of openings or you will leave the default ones in our siding calculator. We can assume that the sizes of the door and windows are standard, and there's no need to modify them. If you need to change them, simply edit their height and width in the respective fields.

  2. Input the number of openings. In our case, it's one door and two windows.

  3. Choose the waste factor. We're going to assume we need to buy 5%5\% more material to account for the trimming.

  4. Our siding calculator will use the formula we mentioned above to find the total area of the siding. It's equal to 108 m2108\ \mathrm{m^2}.

  5. Input the unit price – we'll assume a price of 18 €/m218\ \text{€}/\mathrm{m^2}.

  6. Multiply the area by the unit price to find the total price:

price=18 €/m2×108 m2=1,944\footnotesize \qquad \begin{split} \mathrm{price} &= 18\ \text{€}/\mathrm{m^2} \times 108\ \mathrm{m^2}\\ &= \text{€}1,\!944 \end{split}

Voilà! The total cost of siding material is equal to 1, ⁣944\text{€}1,\!944. Naturally, it doesn't take into consideration the costs of labor, equipment, or additional elements such as connectors – make sure to include them in your calculations afterward!

Types of siding

A wide range of siding materials is available on the market, ranging from vinyl (we made a specific tool for this material, the vinyl siding calculator), through brick and wood, to stucco siding (a traditional Spanish siding). In the following section, we will focus on the most common types.

  • Vinyl siding is by far the most popular type of siding. It is both durable and cheap, which – combined with a wide offer of various colors – makes it the most obvious choice. It can easily last 30-40 years, is relatively easy to clean, and can be chosen in many variants, including an option with additional insulation. Its main drawback is that it's not waterproof – if you don't pay enough attention during the installation phase, water can seep behind the panels and induce damage to your walls.

  • Metal siding is also a popular type. It looks stylish and is water-, weather- and fire-resistant. Still, it is considerably heavier than vinyl, which drives up the installation costs. Moreover, it is prone to mechanical damage such as scratching or impact.

  • Wood siding looks natural and eco-friendly, so it's no wonder that many homeowners decide to choose this option. It is the most ecological of all the available options, has excellent insulating properties, and – if damaged – can be easily replaced. However, it is not that resistant to damage; both water and insects can weaken your siding. The maintenance costs are high, too – you should repaint it every 4-5 years.

  • Brick siding is undoubtedly the most durable option – such siding can withstand over 100 years of exposure to bad weather, such as rain or extremely low temperatures. It is fireproof, resistant to water and insects, and simply the most durable material on the market. The main drawback is, as you could expect, the cost and the high effort required for installation.

Bogna Szyk
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