Deck Stain Calculator

Calculate gallons of stain needed to cover a deck surface.

⏱ Updated: 18 Sep 2026

Calculator

Free deck stain calculator: find gallons of stain needed to cover a deck surface.

Gallons Needed
1-Gallon Cans to Buy
Deck Area
sq ft

Two coats is the usual recommendation for horizontal decking, which takes more foot-traffic wear than a vertical fence. 200 sq ft per gallon is a typical mid-range rate — check your product label, since it swings with wood porosity and application method.

Enter deck dimensions, coverage rate, and coats to calculate gallons of stain needed.

How to Use the Deck Stain Calculator

Enter the deck's length and width, the product's coverage rate, and how many coats the job calls for. Two coats is the default, since decking, unlike a fence face, takes direct foot traffic and weather from above.

A deck surface wears differently than a vertical fence face — rain pools rather than running off, and feet grind grit into the finish daily — part of why deck stain schedules lean toward two coats where a fence often gets by with one.

The Math

gallons = ceil((deck area × coats ÷ coverage rate) × 4) ÷ 4
cans to buy = ceil(gallons)

The gallon figure rounds to the nearest quarter, since that's how most stain is actually measured out; the can count rounds up to a whole number, since stores don't sell partial cans.

Railings and Balusters Aren't Included

This calculator only covers the flat deck surface. Railings, balusters, stair stringers, and skirting all add their own surface area and typically eat stain faster per square foot than a flat board, thanks to all the extra edges. Budget extra product for a deck with substantial railing.