What coverage rate does this calculator use?

New or smooth wood: 300 sq ft per gallon. Weathered or previously stained wood: 200 sq ft per gallon. Rough or porous wood: 150 sq ft per gallon. These match typical manufacturer specs for solid and semi-transparent stains.

Should I count the area of railings and spindles?

The calculator adds a 10% waste factor which covers most railing and edge work on a standard deck. If your deck has very heavy railing detail, add the railing face area manually in the extra surfaces field.

How many coats does a deck need?

New bare wood typically needs 2 coats for even color and protection. A deck being re-stained over an existing finish usually needs 1 coat after stripping. Always follow the stain manufacturer's recommendation.

Do I need to strip the old stain first?

If the old stain is peeling or flaking, stripping is required for good adhesion. If it is worn but not peeling, a light cleaning and scuff-sand often suffices. Stripping changes the wood condition — select "weathered" after stripping.

Does the calculator work for deck paint too?

Solid-color deck paints and stains have similar coverage rates (250–400 sq ft/gallon), so the estimates are a useful guide. Check your specific product label and adjust accordingly.

Deck Stain Calculator

Name: Deck Stain Calculator
Availability: InStock
Author: Nham Vu

Enter your deck dimensions, wood condition, and number of coats to instantly find out how many gallons of stain to buy.

Deck Details

Main Deck Dimensions

Length (ft)

Width (ft)

Extra Surfaces (sq ft) — stairs, walkways, etc.

Wood Condition

New / Smooth

Freshly milled, planed, or previously sealed wood — ~300 sq ft/gal

Weathered / Previously Stained

Aged, gray, or stripped wood — ~200 sq ft/gal

Rough / Porous

Rough-sawn, heavily weathered, or pressure-treated — ~150 sq ft/gal

Number of Coats

Enter your deck dimensions above and click Calculate.

Summary