Tree Wood Calculator: Weight, Firewood and Board Feet

How to use the Tree Wood Calculator

Pick the tab that fits what you have. Each tab says who it is for.

• My tree or log: use this if you have a tree or a log and want its weight, firewood and lumber. Type your wood type, like “oak” or “hard maple”. Not sure? Pick “Not sure / Other”.
• Boards I have: use this if you are buying or selling sawn lumber. It counts board feet, and adds the price if you enter one.
• Firewood pile: use this if you have a stacked pile of firewood and want to know how much is there.

No tape measure? Eyeball it. Each size choice shows the inches or feet it stands for:

• You can also count your steps along a log. The calculator counts about 2.5 feet per step.
• Ballpark: if you eyeball a size, count steps, or pick “Not sure / Other”, the answer is labeled “Ballpark”. It is only a rough guide. Measure with a tape for a better number.
• “Not sure / Other” uses the middle values of our 60 woods: 57 lb per cubic foot fresh cut, 37 dry, and 21 million BTU per cord.

How much does a log weigh?

Weight = the log’s volume × the weight of one cubic foot of that wood. Fresh-cut (green) wood weighs much more than dry wood, because it is full of water. This log weight calculator shows both.

• Volume of a round log, in cubic feet: 0.005454 × width (inches) × width (inches) × length (feet).
• Example: a fresh-cut red oak log, 24 inches across and 10 feet long. 0.005454 × 24 × 24 × 10 = about 31.4 cubic feet. 31.4 × 61 lb = about 1,920 lb. Dry, the same log weighs about 1,380 lb. (“Dry” means about 12% moisture, like store-bought lumber.)
• Real logs can be 10% or more off these numbers, so the calculator also shows a range: about 1,720 to 2,110 lb for this log. Bark, branches and leaves are not included.
• The calculator marks every weight “Rough, for planning hauling. Not for rigging.”
• Our crews estimate wood weight when they plan rigging and crane work.
• The weights on this page are estimates only. If you lift or lower wood, follow your rigging plan and your equipment ratings.

H3: Weight of one cubic foot of wood (worked out from USDA Forest Products Laboratory numbers)

Look at sycamore: heavy when fresh cut, light when dry. The difference is water. The calculator has 60 woods.

How much does a tree weigh?

In the “My tree or log” tab, pick “Whole trunk”. Enter the trunk width at 4.5 feet (about chest height) and the trunk height up to the first big branches, and the calculator gives a rough weight for the trunk only.

• Example: a red oak 24 inches across at 4.5 feet, with 40 feet of trunk to the first big branches. The calculator tapers it to about 19 inches at the top. That is about 101 cubic feet, or roughly 6,180 lb (about 3 tons) fresh cut, and about 4,460 lb dry. The branches add more.
• The taper is 1/2 inch every 4 feet. That number comes from the International 1/4-inch log rule, which was made for sawlogs, not whole trees. Treat the answer as rough. For a closer number, weigh the trunk log by log with the “A log” choice.
• Can’t reach the trunk? Eyeball the width (a bear hug is about 19 inches) and the height in stories. The answer is a ballpark.
• Need the trunk width? Use the tree diameter calculator. Need the height? Use the tree height calculator (link goes live with that page).

How do you calculate board feet?

Multiply the thickness in inches by the width in inches by the length in feet. Then divide by 12. The “Boards I have” tab is a board foot calculator that does this for you.

One board foot is a piece of wood 1 inch thick, 12 inches wide and 1 foot long. Use the real size of your boards.

• Example: 10 boards, each 2 inches thick, 6 inches wide and 8 feet long. 2 × 6 × 8 ÷ 12 = 8 board feet each, or 80 board feet in all.
• Price: add a price per board foot, and the calculator gives the total. For example, at $5 a board foot, 80 board feet comes to $400. (That price is only an example. Lumber prices vary a lot.)

How many board feet are in a log?

It depends on the log rule your buyer uses. In the “My tree or log” tab, the calculator counts the lumber with the International 1/4-inch rule, one common way to count the lumber in a log. Open “Other log rules” to see the Doyle and Scribner numbers too. Log buyers measure across the small end of the log, inside the bark.

For example, a 16-foot log that is 16 inches across the small end scales:

• International 1/4-inch: the most consistent of the three.
• Doyle: subtract 4 from the small-end width in inches, square it, multiply by the length in feet, and divide by 16. It is widely used across the southern U.S. It underestimates small logs, so it often gives the lowest number for logs under about 30 inches.
• Scribner: built by drawing 1-inch boards inside a circle. The common Scribner Decimal C table rounds to the nearest 10 board feet, so a buyer’s tally can differ a little from the formula number.
• Long pieces: the calculator cuts them into logs of 16 feet or less and scales each log at its small end. (Logs longer than 20 feet are scaled as 2 logs.) The 24-inch red oak trunk above, 40 feet long, becomes 3 logs of about 13 feet: about 770 board feet (International), 734 (Scribner) or 699 (Doyle).
• Too small: a log needs at least 6 inches across the small end and 4 feet of length to count as lumber.
• Log rules measure inside the bark, so a real count can be a little lower.
• Tip: ask your buyer which rule they use before you compare offers.

How much wood is in a cord?

A cord is a tight stack 4 feet high, 4 feet deep and 8 feet long: 128 cubic feet. Only about 80 cubic feet of that is solid wood, and the rest is air gaps and bark. The “Firewood pile” tab is a cord of wood calculator: measure your pile, or eyeball it.

• Solid wood: from about 65 cubic feet (small, crooked pieces) to about 90 (big, straight pieces).
• Face cord or rick: 4 feet high, 8 feet long and one piece deep. With 16-inch pieces, a face cord is 1/3 of a cord. With 24-inch pieces, it is 1/2.
• Pickup loads: a full-size bed (about 5.5 by 8 feet and 20 inches deep), loaded level with the sides, holds about 1/2 cord. A small bed (4 by 6 feet) holds about 1/3 cord.
• Example: a pile 4 feet high and 24 feet long, made of 16-inch pieces. 4 × 24 × 1.33 ÷ 128 = 1 full cord.
• Eyeball example: a stack about waist high and the length of a car (about 3 by 15 feet), with 16-inch pieces, is about 0.47 cord. That is a ballpark.
• From a tree or log: the “My tree or log” tab divides the solid wood by 80. The 24-inch, 40-foot red oak trunk above makes about 1.27 cords, or about 3.8 face cords of 16-inch pieces.
• Buying tip: a cord is defined by law. Words like “face cord,” “rick,” “truckload” and “pile” have no legal meaning, and firewood should be sold only by the cord or part of a cord. If a delivery comes up short, contact your state’s weights and measures office before you burn any of it.

What is the best firewood to burn?

Dense hardwoods give the most heat per cord. On Penn State Extension’s chart, Osage orange, hickory and ironwood come out on top. Pick a wood type in the “Firewood pile” tab to see its heat and weight.

H3: Firewood BTU chart: heat per air-dried cord, some common woods (million BTU; BTU is a unit of heat)

*Worked out by our team with the same method, from USDA wood numbers. The calculator’s full chart ranks 28 woods.

• One cord of hardwood gives about as much heat as 108 gallons of heating oil or 165 gallons of propane, in a stove that is 50% efficient.
• Check your mix. Burning a lot of very hot wood, like Osage orange or ironwood, can burn through the bottom of some stoves.
• Never burn poison ivy, poison oak, poison sumac, or wood that has been treated or stained.

How long does firewood need to dry?

Most dense hardwoods need at least a year to dry. Dry firewood (about 20% moisture) gives about 7,100 BTU per pound, but fresh-cut wood (about 75% moisture) gives only about 4,900.

• Split the wood, then stack it in loose piles off the ground. The more wood surface the air can reach, the faster it dries.
• A spot in the sun, covered on top and open on the sides, keeps rain and snow off.