Log Weight Calculator: Green and Seasoned Weight of a Log by Species, Diameter and Length
Estimate how much a log weighs, green or seasoned, from its species, end diameters and length, using USDA weights per cubic foot for 42 species, with logs per truckload and a species comparison.
How it works
weight = volume × weight per cubic foot · volume (straight log) = π × (D ÷ 2)² × L · volume (tapered log, frustum) = π × L × (D₁² + D₁D₂ + D₂²) ÷ 12 · logs per load = payload ÷ weight per log (rounded down)
A log’s weight is its volume times the weight of a cubic foot of that wood in its current condition. Volume comes from the end diameters and length: a straight log is a cylinder, and a log that tapers from one end to the other is treated as a cone frustum, π × L × (D₁² + D₁D₂ + D₂²) ÷ 12, which is more accurate than using one end or the average diameter. The weights per cubic foot come from the USDA Forest Products Laboratory table of woods grown in the United States, both green (freshly cut, full of sap) and air-dry at 12% moisture. Freshly cut wood is often half water by weight, so a green red oak log is about 43% heavier than the same log seasoned: 63 vs 44 lb per cubic foot. Logs in the round dry slowly through the ends, so for anything cut within the last few months use green weight. Add a payload under More options to see how many logs your truck or trailer can carry, and compare the same log across ten common species in the table and chart. Unlike the firewood cord calculator, which works with stacked split wood and cords, this one weighs individual round logs; for board-foot scale use the log volume calculator. Weights are averages: individual trees vary by about ±10–15%, and bark, rot and branch stubs are not included.
Worked example
A green red oak log 16 in across and 8 ft long: the volume is π × (16 ÷ 24 ft)² × 8 = π × 0.667² × 8 = 11.17 cu ft. At 63 lb/ft³ it weighs 11.17 × 63 = 704 lb (319 kg). Seasoned to 12% moisture (44 lb/ft³) the same log would weigh 491 lb, so drying removes about 212 lb of water (30%).
Sources: USDA Forest Products Laboratory Tech Note 218, Weights of various woods grown in the United States (reproduced table) · Engineering ToolBox: Wood species, moisture content and weight · Omni Calculator: Log weight (green densities, pickup truck example)
Frequently asked questions
How much does a log weigh?
Multiply its volume by its weight per cubic foot. A cubic foot of green hardwood typically weighs 45–65 lb (oaks 62–63, hickory 64, sugar maple 56), and green softwood 30–55 lb. A green red oak log 16 in thick and 8 ft long holds about 11.2 cu ft and weighs about 700 lb.
How much does a 12 ft log weigh?
It depends on the diameter and species. A 12 ft green red oak log 12 in across holds π × 0.5² × 12 = 9.4 cu ft and weighs about 594 lb; at 18 in across it holds 21.2 cu ft and weighs about 1,336 lb. Doubling the diameter quadruples the weight.
How much lighter is seasoned wood than green wood?
Wood air-dried to about 12% moisture typically weighs 10–45% less than when green: white ash drops only from 48 to 42 lb/ft³ (13%), while red oak drops from 63 to 44 lb/ft³ (30%). Softwoods with wet sapwood, such as hemlock and eastern white pine, can lose 30–45%.
How many logs can my pickup truck carry?
Divide the truck’s payload by the weight of one log. A half-ton pickup with about 1,500 lb of payload can carry two green red oak logs 16 in × 8 ft (about 704 lb each). Enter your payload under More options to check your own logs, and remember the payload includes passengers.
Should I measure the diameter with or without bark?
Measure inside the bark, because the USDA weights are for wood only. Bark adds weight on top of the result, more on thick-barked species such as oaks and cottonwood.
Related calculators
Weights are estimates for planning. Moving and loading logs is dangerous: stay within your equipment’s rated capacity and use proper rigging.