Deck Stain Calculator

Use the calculator below to estimate how much material you’ll need to paint or stain a deck.

Deck Size
Paint or Stain Details

Stain Estimate:

Total Stain Needed:
Stain Needed per Coat:
Total Square Footage:
Learn how we calculated this below

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How to Estimate Paint or Stain for a Deck

Over time, wooden decks can become weathered and dull, and they’ll need a fresh coat of paint or stain to restore their beauty and protection. Before you start the staining process, you need to estimate how much paint or stain you’ll need to complete the project.

There are a few things you need to do to estimate stain for a deck.

Before you start your project

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Step One: Measure the Deck

Measure the length and width of the deck, then multiply them together to find the total square footage. Repeat this process for each rectangular section of the deck.

If you’re finishing the stairs, then you’ll need to measure the width and depth of each tread, and multiply them together to find the square footage. Then multiply this by the number of steps.

If you’re finishing the railing, then you’ll need to measure the length and height of the railing, and multiply together to approximate the square footage. The railing square footage will be a rough estimate, but since the balusters need to be coated on four sides, this should be reasonably close.

Add all of these square footage measurements together to estimate the total square footage.

Step Two: Note the Type of Wood

The type of wood you’re trying to finish will determine how much stain you need to cover it fully. Softwoods, such as pine, will absorb more than hardwoods, such as cedar.

A new deck constructed using new, unfinished lumber will also absorb more finish than one that has previously been stained.

The age of the deck will also play a role. Significant weathering causes the grain of the wood to open and will require much more stain to get full coverage than wood that is not heavily weathered.

If there are any sections of the decking that are beyond repair, then it’s best to fix them before you apply the new finish so they blend with the rest of the deck. Learn more about how much it costs to repair a deck.

Step Three: Choose a Stain Product

Each type of paint or stain varies in how much square footage it will cover per coat. Check the can to find the coverage rate for the specific product you intend to use.

Typically, one gallon of paint or stain covers around 175 square feet of decking.

Step Four: Calculate the Amount of Stain Needed

Once you have the measurements of the deck and the coverage rate for the product you’re using, it’s time to calculate how much stain you need.

Start by dividing the square footage of the deck from step one by the coverage rate of the product you’re using.

Then, multiply that by the number of coats you want to apply. Typically, two coats are required to get a good finish, but keep in mind that very light or dark colors may require an additional coat.

You should also consider adding an extra 10% of additional stain to account for spillage, drips, waste, etc.

In general, refreshing a deck with a few coats of stain is a cost-effective way to restore its beauty and add a layer of protection.

You might also be interested in calculating stain for a fence.