Fence Stain and Sealant Coverage Calculator
Calculate how many gallons of stain or sealant you need to cover your fence, accounting for fence style, number of coats, and waste factor.
Check your product label. Typical range: 150–400 sq ft/gal.
Recommended: 10% for smooth surfaces, 15–20% for rough or weathered wood.
Formula
1. Gross Area = Fence Length × Fence Height × Number of Sides
2. Net Paintable Area = Gross Area × Fence Style Factor
(Solid = 1.00 | Stockade = 0.85 | Shadowbox = 0.75 | Split Rail/Picket = 0.50)
3. Total Area = Net Paintable Area × Number of Coats
4. Raw Gallons = Total Area ÷ Coverage Rate (sq ft/gal)
5. Adjusted Gallons = Raw Gallons × (1 + Waste Factor / 100)
6. Gallons to Purchase = ⌈ Adjusted Gallons ⌉ (rounded up to nearest whole gallon)
Assumptions & References
- Typical stain/sealant coverage is 150–400 sq ft per gallon depending on product viscosity and wood porosity; always check the product data sheet.
- A 10% waste factor is standard for smooth, new wood; increase to 15–20% for rough-sawn, weathered, or highly porous wood.
- Fence style factors reflect the ratio of solid wood surface to total fence face area (open gaps reduce the paintable surface).
- Two coats are recommended for new or bare wood; one coat may suffice for maintenance re-coating over an existing finish in good condition.
- Posts and rails are not separately calculated; they are assumed to be included within the overall fence face dimensions.
- Coverage rates sourced from manufacturer guidelines (e.g., Cabot, Ready Seal, TWP, Armstrong Clark) and the Paint Quality Institute recommendations.
- Always stir product thoroughly and apply in dry conditions (no rain forecast for 24–48 hours) for best adhesion and coverage.