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ReferenceCalculators for wood slabs and countertops
SlabHome editorial team · Last reviewed October 2026
Three numbers decide most practical questions about a wood top before it is made: how much it will move as the seasons change, how much it will weigh and how much area it covers. Each can be estimated from a few inputs.
What each calculator answers
| Question | Inputs | Output | Use it for |
|---|---|---|---|
| How much will the top change width? | Species, width, grain orientation, moisture change | Change in width in mm | Gaps at walls, fixings, slots in the base |
| How heavy is the top? | Length, width, thickness, species, moisture content | Net weight in kg and lb, crate size and crate volume | Base design, crate, freight, lifting |
| How much area does the top cover? | Length and depth of each section, cutouts, a waste allowance you type | Area in ft2 and m2 | Comparing quotes by area, checking an order |
The movement calculator uses the method and coefficients of the USDA Forest Products Laboratory Wood Handbook. For weight, multiply length by width by thickness in metres and by the density of the species in kg/m3: a 2400 x 900 x 38 mm top at 610 kg/m3 weighs about 50 kg before finish. The wood slab weight calculator does the sum for nine species, adjusts it for moisture content and adds the crate size and volume. The countertop square footage calculator adds up the sections of an L-shaped or U-shaped top, takes off the cutouts and gives square feet and square metres.
Where the numbers lead
- Gaps and fixings for wide tops are discussed on the live edge countertop page.
- Species densities and movement are compared on the slab species overview.
- Moisture targets at delivery are covered in wood slab moisture content.
When the numbers work, send a request with the size and species.
Frequently asked questions
How accurate are these calculators?
They give typical values from published coefficients. Real boards vary with density, grain angle and drying history, so use the result to plan gaps and fixings, not as a promise for one piece.
Last reviewed October 2026. Figures are typical values from the sources named above, never a promise for one piece.
Describe the top you want
Size, species, style, finish and where it is going. SlabHome matches you with up to 3 workshops that reply with photos of the actual piece and a quote. Free for buyers, reply within 24 business hours.