Formula
Net surface area × coats ÷ coverage per gallon = gallons. Apply allowance, then round up to whole containers.
Deck Stain Calculator
Estimate stain gallons and whole containers from surface area, coats, and product coverage.
How this deck stain estimate works
Stain usage changes with wood age, porosity, texture, and application method. Measure the surfaces, count the coats, and replace the default coverage with the product label when available.
Worked example
A 300 sq ft deck at two coats and 300 sq ft per gallon per coat needs about 2 gallons before any product-specific adjustment.
Before you buy
Buy enough of one batch to keep color consistent, especially for large surfaces. Check recoat timing and whether the label coverage assumes smooth or weathered wood.
Assumptions
Defaults are starting points. Replace coverage, density, package yield, spacing, and allowance values with the product or plan you are actually using.
Limitations
The estimate does not predict primer, tint, sheen, stripping, cleaning solution, or the extra stain used on railings and complex details unless they are measured.