About this calculator
Stain, oil or sealer for a whole deck, including both faces of the railings and the steps, adjusted for weathered wood.
How it’s calculated
Area = deck + 2 × railing length × height × 1.2 (allowance for spindles) + steps. Amount = area × coats ÷ coverage. Rough or weathered wood is assumed to drink about a third more.
Worked example
With these inputs:
- Deck length
- 4.8 m
- Deck width
- 3.6 m
- Railing length
- 8 m
- Railing height
- 900 mm
- Steps
- 3
- Wood condition
- New / smooth
- Coats
- 2
- Coverage (m² per litre)
- 8
the result is:
- Stain needed
- 9 L
- Deck surface
- 17.28 m²
- Railing (both faces)
- 17.28 m²
- Total area
- 35.91 m²
Tips from the trade
- Clean and brighten the wood first. Stain won’t stick to grey fibres.
- Do a water-drop test: if water beads, the wood isn’t ready to take stain.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the Building Regulations before ordering.