What this calculator does
Timber weight is volume times species density. A standard 2×6 eight feet long weighs 15.6 pounds in Douglas fir, but 20.2 in red oak and only 10.5 in western red cedar.
Species matters nearly as much as size. Red oak is almost twice the density of cedar, so a stack that one person can shift in cedar is a two-person lift in oak. The figures here are for kiln-dried timber; green or wet lumber can weigh half again as much and sometimes more.
The formula
The board volume in cubic feet is the thickness and width in inches divided by twelve each, multiplied by the length in feet. Multiplying by the species density and the board count gives the total weight. Densities are for kiln-dried material at typical moisture content.
| Term | Meaning |
|---|---|
| Density | Pounds per cubic foot at kiln-dried moisture content. |
| Kiln-dried | Timber dried to around 12 to 19% moisture, which is what these densities assume. |
| Green lumber | Freshly sawn and undried, substantially heavier than kiln-dried. |
| Actual dimensions | A 2×6 measures 1.5 by 5.5 inches, which is what to enter. |
The inputs explained
| Field | What to enter |
|---|---|
| Species | Species, which sets the density. Softwoods cluster around 23 to 36 lb/ft³; hardwoods run higher. |
| Board thickness (in) | Board thickness in inches. Use actual dimensions: a 2×6 is 1.5 inches thick. |
| Board width (in) | Board width. A 2×6 is 5.5 inches wide. |
| Board length (ft) | Board length in feet. |
| Number of boards | Number of boards. |
When to use it
Planning a delivery
A pack of timber weighs more than people expect and may need machine handling.
Checking a load limit
Vehicle and trailer capacities are quickly reached by a modest quantity of timber.
Estimating a structure dead load
The self-weight of framing is part of what the structure below must carry.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How much does species change the weight?
The same board in a range of species.
| Species | Total weight | In kilograms | Volume per board |
|---|---|---|---|
| Western red cedar | 10.5 lb | 4.8 kg | 0.458 ft³ |
| Spruce-pine-fir | 13.3 lb | 6.0 kg | 0.458 ft³ |
| Douglas fir | 15.6 lb | 7.1 kg | 0.458 ft³ |
| Red oak | 20.2 lb | 9.1 kg | 0.458 ft³ |
Questions
Should I use nominal or actual dimensions?
Actual. A 2×6 measures 1.5 by 5.5 inches, not 2 by 6, and entering nominal dimensions overstates the weight by about 40%. Nominal sizes are a naming convention left over from rough-sawn timber before surfacing.
How much heavier is green lumber?
Substantially, often 50% more and sometimes double for freshly sawn softwood. Green timber can be well over half water by weight. These densities assume kiln-dried material, so a delivery of green lumber will be heavier than calculated.
Why does species matter so much?
Because density varies nearly twofold across common construction timbers, from about 23 lb/ft³ for western red cedar to 45 for hard maple. Density also tracks strength and hardness, which is why the heavier species are used where those matter.
Does moisture content change over time?
Yes. Timber equilibrates with the surrounding humidity, gaining and losing weight with the seasons. Kiln-dried lumber stored outside will pick up moisture and get heavier. The variation is usually a few percent, which rarely matters for an estimate.
For lumber volume in board feet, see the board foot calculator. For metal weights, see the metal weight calculator.