How much does a 2x4 weigh?

An 8 ft kiln-dried southern yellow pine 2x4 (actual size 1.5 x 3.5 in) weighs roughly 4.79 kg (about 10.6 lb). Species and moisture state both shift this: the same board green (freshly cut) weighs closer to 7.66 kg (about 16.9 lb).

Does green lumber weigh more than kiln-dried lumber?

Yes — green (freshly cut) lumber can weigh around 60% more than the same board kiln-dried, since it still holds much of its original moisture. Air-dried lumber sits in between, roughly 12% heavier than kiln-dried.

What does 'KD' mean on a lumber stamp?

KD (kiln-dried) means the board has been dried in a controlled kiln to roughly 19% moisture content or less, rather than air-dried or left green. KD lumber is lighter, more dimensionally stable, and is the standard for most retail framing lumber in the US.

Lumber Weight Calculator | Dimensional Lumber Weight by Species (lb)

Lumber Weight Calculator: How Much Does Dimensional Lumber Weigh?

A board's weight matters well beyond curiosity — it sets the freight cost on a delivery, the load a truck bed or trailer can actually carry, and whether one person can lift a beam alone on site. This calculator works out that weight from a board's length, width and thickness, its wood species (each with its own density), and its moisture state, since a freshly cut board carries far more water weight than a kiln-dried one.

How to Use This Calculator

Enter the board's length, width and thickness, choosing a unit for each (mm, cm, m, ft or in).
Set the quantity of identical boards.
Choose a wood species preset — this sets the reference kiln-dried density — or enter a custom density.
Choose the moisture state: kiln-dried, air-dried, or green (freshly cut).
Choose your output mass unit (kg or lb).
Read off the weight per board, the total weight, and the estimated material cost.

The Math Behind the Calculation

A board is a rectangular prism, so its volume is length x width x thickness. Weight = volume x density x quantity, and density itself depends on species and moisture state: each species has a reference density at kiln-dried moisture content (~12%), scaled up for air-dried or green wood since unseasoned timber still holds much of its original water weight.

Worked example: a kiln-dried southern yellow pine 2x4 (actual size 3.5 x 1.5 in, 0.0889 x 0.0381 m), 8 ft (2.4384 m) long. Volume = 2.4384 x 0.0889 x 0.0381 ≈ 0.00826 m³. At a reference density of 580 kg/m³, weight = 0.00826 x 580 ≈ 4.79 kg (about 10.6 lb). The same board green (freshly cut, x1.6 moisture multiplier) would weigh roughly 7.66 kg (about 16.9 lb) — nearly 60% more.

Pro Tips

At a typical US price of around $0.65 per kg of dimensional lumber, this calculator's own worked example — a kiln-dried 2x4, 8 ft long, about 4.79 kg (10.6 lb) — costs roughly $3.11 in material, before any delivery or milling charges.

Moisture state changes weight a lot: green lumber can weigh up to 60% more than the same board kiln-dried, so factor it in before booking freight or checking a lift capacity.
Nominal sizes are not actual sizes — a "2x4" measures 1.5 x 3.5 in once dressed, not a full 2 x 4 in — so measure the real dimensions if you know them.