Timber Volume and Weight Calculator
Volume, board area and weight for timber by species density.
Inputs
Result
Formula
| Volume per piece | V = length × width × thickness in metres |
| Total volume | V × quantity |
| Mass | V × air-dry density |
| Board area | total volume ÷ thickness |
| Pieces per m³ | N = 1 ÷ volume per piece |
| Board feet | 1 m³ ≈ 423.8 bf |
Twenty pieces at 40 × 200 × 50 mm and 500 kg/m³: 0.0400 m³ and 20.00 kg each — 0.8000 m³ and 400.0 kg in total, equivalent to 16.00 m² of 50 mm board.
FAQ
Why is timber sold by volume, not weight?
Because value follows usable volume and yield, not mass. The same volume of pine and hardwood differs twofold in weight yet yields identical members. Selling by weight rewards wet timber — 20-40% heavier but no more product — which is exactly why timber is settled by volume.
How do sawn timber and plywood convert?
By volume: 1 m³ is 20 m² at 50 mm, 33.3 m² at 30 mm and 55.6 m² at 18 mm. But sawn timber is solid and plywood is laminated, so they are far from interchangeable. In formwork the sawn member is the bending-resistant bearer while plywood is the wearing face — quantity them separately.
Does moisture content affect volume much?
Volume little, weight a lot. Drying from green to air-dry shrinks volume 3-8% but cuts mass 20-40%. That is why timber machined straight after delivery comes out undersized, and why timber codes require 15-20% moisture before installation — otherwise it cracks and distorts afterwards.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.