Deck Stain Calculator
Free deck stain calculator. Enter deck size, railing and stain type to get the gallons and quarts of stain you need for the right number of coats.
About the Deck Stain Calculator
Our free deck stain calculator tells you how much stain to buy for your deck. Enter the deck length and width, the railing linear footage and height, the stain type (transparent, semi-transparent or solid) and the number of coats, and the tool returns the total surface area and the gallons and quarts of stain needed. Coverage is tuned to each stain type, and the railing is counted on both faces. Add a waste margin for rough or thirsty wood. Every calculation runs in your browser with no signup — perfect for deck builders, painters and homeowners.
Features
- Gallons and quarts from deck area plus railing
- Coverage tuned to transparent, semi-transparent or solid stain
- Railing counted on both faces for full coverage
- Adjustable coats and waste percentage
- Works for new builds and re-coats
- 100% client-side and private — no signup, no data sent
How to use this tool
The Deck Stain Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter the deck length and width in feet.
- Add the railing linear footage and height (counted both sides).
- Pick the stain type and number of coats.
- Read the gallons and quarts of stain to buy.
Frequently asked questions
How much stain do I need for my deck?
Divide the total surface area (deck boards plus both faces of any railing) by the stain's coverage per gallon, then multiply by the number of coats. This calculator does all of that and returns gallons and quarts.
How many square feet does a gallon of stain cover?
Transparent stains cover about 250–300 sq ft per gallon, semi-transparent about 200–250, and solid stains about 150–200 because they form a thicker film. The calculator uses a midpoint value for each type.
Should I count both sides of the railing?
Yes. Railing balusters and posts are usually stained on all visible faces, so the calculator counts the railing area twice (both faces). Skipping this is a common reason people run short.
How many coats of stain should I apply?
New or bare wood usually needs two coats; a re-coat over sound stain often needs one. Thirsty or weathered boards absorb more, so add a waste margin and test a small area first.
Is this deck stain calculator free?
Yes, completely free with no signup. Every estimate runs in your browser, so nothing is uploaded or tracked.
Using the results
The Deck Stain Calculator estimates quantities from your measurements and the stated assumptions. Check dimensions, product coverage and project requirements before buying materials.