Lumber Weight Calculator

How to calculate lumber weight from dimensions

The calculation uses two steps. First, compute board feet from the board's dimensions:

Board Feet = (Thickness × Width × Length) ÷ 12
Thickness and width in inches; length in feet.

Then convert board feet to weight using the species density from the table above:

Weight (lbs) = Board Feet × Density (lb/ft³) ÷ 12

Example: A 2×6×10 board (nominal) of dry Douglas Fir-Larch:
Board feet = (2 × 6 × 10) ÷ 12 = 10 BF
Weight = 10 × 32 ÷ 12 = 26.7 lbs

For more accurate results, use actual dimensions rather than nominal. A 2×4 is actually 1.5" × 3.5"; a 2×6 is 1.5" × 5.5". The difference matters — nominal dimensions can overstate board feet and therefore weight by 30–43% on framing lumber. Hardwood from a rough-sawn yard is typically closer to nominal thickness, so check with your supplier.

How to use this calculator

Two input modes let you start from whatever information you already have:

• Enter Dimensions mode: Enter thickness and width in inches (decimals and fractions like 5/4 or 1 1/2 both work), then length in the split ft and in fields, and quantity. Use the 4/4, 5/4, 6/4, 8/4 preset chips to fill in common rough-sawn hardwood thicknesses with one click.
• Enter Board Feet mode: If you already know the board foot total from an invoice or quote, enter it directly. No dimension breakdown needed.

In both modes, select the wood species from the dropdown — softwoods and hardwoods are grouped separately. Then choose the moisture condition: Dry (~12% moisture content, kiln-dried) or Green (freshly sawn). Results appear instantly in pounds, US tons, and kilograms, along with weight per board foot for the selected species.

The Download PDF Report button generates a formatted summary with all inputs and results — useful for freight quotes, load planning, or project documentation.

Green vs dry lumber weight

Green lumber (freshly sawn) contains significant moisture in the wood cells. The weight difference between green and kiln-dried varies significantly by species:

• Douglas Fir-Larch: 38 lb/ft³ green vs 32 lb/ft³ dry — about 19% heavier green
• Southern Yellow Pine: 41 lb/ft³ green vs 34 lb/ft³ dry — about 21% heavier green
• Red Oak: 64 lb/ft³ green vs 44 lb/ft³ dry — about 45% heavier green
• Hard Maple: 54 lb/ft³ green vs 44 lb/ft³ dry — about 23% heavier green

Kiln-dried (KD) framing lumber is typically dried to 12–19% moisture content. Flooring, furniture, and cabinet stock is dried further to 6–8%. Air-dried lumber falls between green and KD values — typically 15–20% MC depending on climate and drying time — so estimate a weight midway between the two values shown by this calculator.

For freight estimates, always confirm with the yard whether stock is green or KD before calculating truck loads. A single flatbed with 3,000 BF of green Red Oak carries roughly 16,000 lbs of wood — the same BF of kiln-dried Oak weighs about 11,000 lbs.

Why species density varies so much

Wood density is primarily determined by two factors: the thickness of individual cell walls and the ratio of dense latewood (summer growth rings) to lighter earlywood (spring growth). Slow-growing trees in challenging conditions develop thicker cell walls and therefore denser wood.

This produces a wide range across commercial species:

• Lightest domestic softwoods: Eastern White Pine (~25 lb/ft³ dry), Spruce (~27 lb/ft³ dry) — used for pattern work, light framing, and trim where weight is a concern
• Common framing softwoods: Douglas Fir, Southern Yellow Pine, Hem-Fir — 29–34 lb/ft³ dry
• Light hardwoods: Aspen, Basswood, Butternut — 24–28 lb/ft³ dry
• Common cabinet hardwoods: Cherry, Walnut, Maple, Oak — 36–48 lb/ft³ dry
• Dense hardwoods: Hickory, Pecan — 50–56 lb/ft³ dry

This is why a truckload of hardwood flooring weighs dramatically more than the same volume of framing lumber. Never use a generic "lumber density" — always look up the specific species.

Nominal vs actual dimensions and lumber weight

Dimensional lumber is sold by nominal size but cut to smaller actual dimensions. This affects weight calculations significantly:

• A nominal 2×4 is actually 1.5" × 3.5" — nominal board feet are (2 × 4 × L) ÷ 12 = 0.67 BF/LF; actual is (1.5 × 3.5 × L) ÷ 12 = 0.44 BF/LF. That is 34% less wood.
• A nominal 2×6 is actually 1.5" × 5.5" — nominal gives 1.00 BF/LF; actual gives 0.69 BF/LF. Again about 31% less.

For S4S (surfaced four sides) dimensional lumber from a home center or building supply, always enter actual dimensions. For rough-sawn hardwood from a lumber yard, 4/4 stock is typically surfaced to about 13/16" or sold at 1" actual — confirm with your supplier which thickness they guarantee.

The calculator accepts any decimal or fraction for thickness and width, so entering actual values is straightforward.

Why lumber weight matters

• Structural dead loads: Floor joist sizing, deck beam spans, and roof rafter tables all depend on the dead load of the framing. Species choice affects these calculations, especially for heavy hardwood flooring over wood subfloor.
• Freight costs: Shipping lumber is weight-based. Large hardwood orders can weigh far more than expected — 1,000 BF of green Red Oak weighs approximately 5,300 lbs, which is nearly the entire net payload of a standard pickup truck.
• Vehicle load limits: A full pickup truck bed of green hardwood can easily exceed the truck's rated payload capacity (typically 1,500–2,000 lbs for half-ton trucks). Calculate the weight before loading.
• Kiln scheduling: Commercial kilns estimate drying time and energy cost from the green weight and target moisture content. The green-to-dry weight loss is a direct indicator of how much water must be removed.
• Project budgeting: If you are paying for lumber delivery by weight (common for timber orders), accurate weight estimates prevent billing surprises.

A practical example

A furniture shop orders 500 board feet of 4/4 black walnut from a local hardwood dealer. The dealer offers both kiln-dried and green stock at different prices. Here is what each option weighs:

• Dry walnut (38 lb/ft³): (500 ÷ 12) × 38 = 1,583 lbs
• Green walnut (50 lb/ft³): (500 ÷ 12) × 50 = 2,083 lbs

The green stock is 500 lbs heavier — a difference that matters when the shop's van has a 1,800 lb payload limit. In this case, green walnut would require two trips or a rental truck. Kiln-dried walnut fits in one load with 200 lbs to spare for packaging and equipment.

To run this calculation yourself: switch to "Enter Board Feet" mode above, type 500, select Black Walnut from the species list, and toggle between Dry and Green to compare.

Frequently asked questions

← Board Foot Calculator · Lumber Project Estimator · Linear Board Foot Calculator · BF ↔ Linear Feet Converter