Wood finish quantities
Use actual coated area, coat count and product coverage
Back to calculator ↑Count coated faces
Measure one face and multiply by faces actually coated. Edges and complex profiles may need separate measurement.
Measure the actual timber faces to be coated in metres. If front and back are equal, increase the face count; measure and add edges, battens, fence palings and mixed sizes separately. Do not automatically double a deck that will be coated only on top. Surface preparation or replacing damaged wood may add surfaces rather than reduce the coating area.
Use label coverage
Coverage in m²/L/coat varies with finish, timber porosity and application. Use the chosen product label, not the default as a specification.
Coverage means square metres per litre for one coat and should come from the selected product’s label or data sheet. A manufacturer figure for smooth planed timber may differ from rough or weathered wood. The 10 m²/L/coat default is an example, not a product promise. Calculate primer, topcoat or different finishes separately when their rates differ.
Default example
A 5 × 3 m single face is 15 m². Two coats mean 30 m²-coats; divide by 10 m²/L/coat to get 3 L. Ten percent allowance gives 3.3 L. One 3.5 L can meets the estimate. If the product comes in 1 L cans, buy four cans; do not round 3.3 down to three.
Choose packaging
Divide required litres by actual can size and round up. Check whether primer or a different coating is also required.
Before ordering, check the product’s coat count, recoat time, compatibility with existing finishes and exterior suitability. Some systems require a primer or specific sequence, so litres alone cannot select a product. Blank price means unknown and produces no cost figure; entered zero means a known zero. The amount shown excludes brushes, cleaning materials and labour.
Common questions
How do I include two faces?
Choose two faces only when their areas and finish are the same. If one side has openings or different detail, calculate it separately and combine litres for the same product.
Does allowance include primer?
Primer is excluded because its coverage and coat count may differ from the finish. Estimate each distinct product from its own label before combining a shopping list.
What does a zero price mean?
Zero is a deliberately known zero cost; blank does not fabricate a price. Confirm that the entered can volume and can price refer to the same product size.
Sources and calculation guidance
Check these against your chosen product’s label and instructions.