The Formula

Hardwood lumber weight is calculated at a specific moisture content, using a measured amount of lumber. The majority of the hardwood lumber available to the average woodworker has been kiln dried to a specific moisture content. Tables have been established to calculate the weight of 1,000 board feet, 1 inch thick, with a moisture content of between 12 and 15 percent. The tables refer to a unit, or "bunk," of lumber that is equal to 1,000 board feet. For example: The weight of a bunk, or unit, of alder is between 2,000 and 2,400 pounds depending on how it's surfaced. A unit of red oak weighs between 3,100 and 3,800 pounds. A unit of cherry weighs between 2,750 and 3,400 pounds. Maple weighs between 2,350 and 3,500 pounds.

Weight by Board Feet

The weight of a moderate amount of hardwood -- a pickup bed with a single layer, for example -- can be calculated by weighing a single board foot on a bathroom scale. Once that's established, the total weight can then be calculated by multiplying the total number of board feet in the pickup bed by the weight of the example board foot. A board foot measures 12 by 12 inches and is 1 inch thick. Even though the lumber may measure only 3/4 inch thick, it is calculated as 1 inch. For example, if the accumulated width of a single layer of lumber in the pickup bed measures 48 inches wide and 96 inches long -- 4 by 8 feet -- the total number of board feet is 32. Multiply 32 by the weight of the example board foot for the weight of the lumber in the pickup.

How Much Can the Pickup Carry?

Many pickups are rated to carry a half ton. One way to get a rough idea of how much lumber you can safely haul is to start with a reference. For example, a unit of red oak weighs no more than 3,800 pounds. Round it up to 4,000 pounds and divide it by 1,000 pounds, or 1/2 ton, to get 4. This means you could safely place one-fourth of the unit on the pickup at once. It's possible to count the layers in an ordinary unit and get approximate divisions for weight. Most, if not all, forklifts have scales. If you have any doubt about the weight capacity of your vehicle, instruct the forklift driver to call out or write down the weight by picking up the load with the forklift. You may have to stack the lumber on the forks by hand, but you also get to hand-select the best pieces.

Commercial Applications

Weight calculations are typically the concern of dealers, truck drivers and material handlers working with large quantities of hardwood. The weight formula calculated on the 1,000-board-foot bunk is important for selling, buying, shipping and receiving. Semi-truck and forklift drivers rely on established bunk weights for safety and regulations. Lumber buyers and sellers rely on 1,000-board-foot unit weights for calculating cost versus quantity.

Weight and the Janka Scale

Density and weight go hand in hand. The Janka scale rates the density of lumber. The lower the number, the less the density and the lower the weight. The highest numbers represent the wood with the most density and weight. Use the Janka scale as a general guide to compare the weight of different species by comparing the density.