You’ll use board footage when you purchase lumber from a commercial or hardwood lumber yard (instead of per piece pricing), and there are good reasons for it.
When you buy construction-type lumber from the home improvement center, almost always you’ll be buying pieces of lumber that are standard construction sizes, commonly known as “1 by”, “2 by” and “4 by” lumber.
Because there is only a limited amount of these common construction lumber sizes, this works well and is easy to calculate. You simply multiply the piece price by the number of pieces you need, and you know what you’ll be spending.
So, if this works so well, why mess with it? And, WHAT THE HECK IS A BOARD FOOT?
The answer to the first question is “necessity.” A different measurement and pricing system is needed in hardwood and partially dimensioned lumber sales. For one thing, there is almost an infinite amount of sizes in the board bins. Sure, the lengths are familiar. The hardwood dealer we go to has most of the bins filled with 12’ lumber. You can buy a partial length, but at least 4’ must be left “for the next guy.”
However, depending on where the lumber was cut from in the log, how thick it was cut, and how wide a board resulted, there are hundreds of sizes of boards. That’s where board feet come in.
The answer to the second question is that a board foot is a unit of measurement for the VOLUME of wood in a given board. A basic board foot is defined as 12” x 12” x 1”. Multiply these three numbers, and you get 144. 144 what? Cubic inches, that’s what.
There are TWO ways to formally calculate the amount of board footage in any piece of lumber.
If the length of the board is in even feet or easy fractions thereof (halves and quarters), then you use this formula: (length in feet X width in inches X thickness in inches) / 12. Let’s use the example of a board that is 9” wide, 1-½” thick, and 10-½ feet long. Our calculation would be 9 X 1.5 X 10.5. This equals 141.75. Divide this by 12 and you see that you have about 11.81 board feet.
If the board is in an odd length, use a slightly different, but related, method. Use INCHES for the length and divide by 144. The formula will now look like this: (length in inches X width in inches X thickness in inches) / 144. Let’s use the example of a board that is 10” wide, 2” thick, and 140” long. Our calculation would be 10 X 2 X 140. This equals 2800. Divide this by 144 and you see that you have about 19.44 board feet. One last thing. Hardwood lumber is sold in thicknesses expressed in quarters - when the lumber is over ¾” thick. 1” thick is “4-quarter”, 1-¼” is “5-quarter”, 1-½” is “6-quarter”, then you jump to 2” (8-quarter) and then 3” (12-quarter). This is the way the sizes are said, but they read as 4/4, 5/4, 6/4, 8/4 and 12/4.
Also, these are the names of the lumber, but they are approximations of the thickness, as when the lumber is face dressed, it will end up being slightly thinner.
There you have it! Now you can hold a well-informed conversation with your lumber supplier and calculate and communicate confidently.
Hey, Dirt Farmer Jay here from DirtFarmerJay.com. Have you ever gone to the commercial lumberyard
or to a hardwood dealer and they started using this mystical language like board footage and
board feet? What's that all about? Well, stay tuned and I'll put you in the know.
Hey, Dirt Farmer Jay here from DirtFarmerJay.com. Before we get onto the topic of board footage
and how to add that to your list of skills and how to buy lumber that way,
and to understand what's being said, I'd like to invite you to our upcoming live stream on Saturday,
May 2nd. Hey, come social distance with Dirt Farmer Maggie and I as we talk about what's on
your mind in these times of resiliency and self-reliance, more important than ever,
and then also to tell you what's coming up. To find the live stream, just simply go back to the
channel, look up in the list in the videos and for the live stream listing and sign up. And you
can even get a reminder sent to you so you can join it. We're coming up. It'll be great to interact
with you. All right, well, let's talk about board footage. Is this some kind of language that's been
designed to confuse mere mortals like you and I? No, not at all. Just like any industry, there is
language that has been developed that allows those in that industry to be more precise.
Doesn't matter if you're in financial areas, medical, manufacturing, there's always going to
be certain terminologies used and such is the case related to board footage. A board footage is
actually a measurement of volume of lumber, but the first thing that comes to my mind when I first
encountered this years ago is why is it needed? What's the big deal? You can go down to the lumber
yard and buy a two by four, two by six or one by 12, whatever it might be, and just buy it because
it's got the dimensions on it and it's got a price. And so you just buy it by the piece. Why doesn't
that work in the hardwood area? Well, first of all, when you go to the lumber store, the regular lumber
store, your home improvement center, everything is pretty much in standard sizes. There's only a
limited range of items, whether it's one by or two by or four by four or four by whatever. And so
they have a less range of types of lumber and size of lumber. Therefore, it's easy to sell it
by the piece or by the stick as it's called sometimes. So in the retail consumer environment,
that's typically what's used, piece pricing. But when you come over to commercial or buying hardwood
or slabs of hardwood that have a minimal amount of milling, now you've got a lot of variables.
There's lots of different thicknesses and there's also lots of different widths, depending in what
section of log the lumber was cut from and what kind of species and so forth. So you've got to
come up with a way with all these thousands of different dimensions in the lumber racks
of how to commonize the pricing. And that is done through board footage. What is the volume
in each piece of lumber multiplied by the board foot price to get the price for the piece you're
buying? That's how it works. But how does it really work? Okay, well, if you go into the lumber yard
and you buy a two by six, like we said, that's just kind of a standard piece. But the reality is
the nominal size is actually about an inch and a half by five and a half.
Although it's called a two by six, that was the size before it was plain kiln dried or dried
to come up to this standard size, which we all know and love and enjoy. So that's in the case
of retail pricing and sizing. But when you go into a hardwood lumber area, you're more likely to see
pieces of lumber like this. And of course, these are shortened pieces, they'll be anywhere from
six foot, most hardwood manufacturers or suppliers want you to leave at least four
foot of lumber sellable. Some wanted a little bit longer than that, but you're going to buy
stuff that's 12 foot up to 16 foot long, common lengths are 10, 12, and so forth. And to figure
out the size, you've got to use this formula for figuring board footage, you're going to take the
height in inches by the width in inches. And then you can do it either by length in inches, or if
it's even footage or even or easily describe length like two and a half foot, or you know,
six and a half foot or six and three quarter. But if you get into weird fractions, you want to do
inches, you can measure it in inches, or by foot, then you're going to divide that by a different
number. And I'm going to walk you through those stick with me, I know it sounds a little confusing.
But remember, we're talking about volume. Before we get a little bit further on that, though,
I'm going to use this little piece of foam, just to illustrate what a board foot is. Because
remember, a board foot is that volume. And this particular piece of foam is 12 inches wide,
it's one inch thick, and in this case, it's 28 inches long. But a board foot is actually
one inch thick, 12 inches wide, 12 inches long. So if a board foot then has exactly 144
cubic inches of volume in it, that is what a true board foot is. You can commit that to memory,
12 by 12 by one, 144 cubic inches. So when you go different sizes of lumber, what you're trying
to find out is how many board feet or how many of those volumes are in there. And as you know,
volume is a variable thing, I can take a gallon of water and pour it into different things,
it may look like it's different, but it's still a gallon of water. It may be in a real tall
cylinder, it may be in something that's a tray or whatever, it's the same volume,
just in different containers. And so these boards that you see here are different containers,
so to speak, of the volume of wood. Now let's use this as a real simple example, and then we'll
apply it to the others and you'll get this forever and it'll be part of your lexicon.
So as I said, this particular item, if this was a piece of hardwood and it was lengthwise 28 inches
long by 12 inches wide by one inch thick, I would do this math. And I've actually shown you the math
on the side in two different ways. If I was going to calculate it in inches, I would take one inch
thick by 12 inches wide, that's how deep it is this way or wide, by 28 inches long. When I multiply
those three together, I get the number 336. Remember there's 144 cubic inches in each board
foot. I divide 144 into 336 and what do you know? I get two and a third board feet or 2.33.
Now let's suppose that I had something that's real easy to measure it in feet. So instead of
measuring that last number in inches, I could do it in feet and then divide by 12, not 144. So let's
look at that formula. So using length and feet, this exact same volume here, one inch by 12 inches
by 2.33 foot because it was two and a third foot. It was two foot and four inches. Four inches is
one third of a foot. So one by 12 by 2.33. If I multiply those, I come out with 27.96.
Now I divide by 12 because I measured in feet not inches and it comes out, look at that, 2.33,
the same as the other. So there is a real quick example of something of finding how many board
foot is in this object. Well let's look at a couple other examples. We'll go ahead and get
rid of the standard 2 by 6 because that's not really what you're going to buy. But let's
suppose you went down and you bought a piece of lumber. It was something like this but it was
longer. But how much is in this in the way of board footage? Well I've already measured this.
It's 13 and a half inches this way lengthwise. It's one inch thick and it's eight inches wide.
Of course take out the groove there if it was just a solid piece. Well if I take all of those items
and measure it and say eight inches wide by 13 and a half by one divided by 144
is three quarters of a board foot. That piece right there has three quarters of a board foot.
Let's look at this one here. If I bought something like this and of course this is more finished than
you would typically buy. But again we're talking volume. Well if I look at the sizes on this,
we'll just go ahead and use this in. I already marked it here. What I have found is that this
is two and a quarter inches thick 2.25 four and a half inches wide and it is 34.75 or 34 and three
quarters inches long. When I take all of those multiply them I end up with 352 when I divide it
by 144. I have just under two and a half board foot in this piece of maple here. So there we go.
Now let's do one more just to say more naturally how it might look and here it is. Here's a board
that wasn't bought by from a hardware supplier just recently and as you see it's ready to be
thicknessed and planed out to take out the resaw marks and all this. It's soft maple. So when I
went to buy this piece of wood we need to calculate the amount of board footage multiplied by the
board footage price to know how much it's going to pay and that's really important for you to know.
So again we're going to look at our math on this and I've just done it to cheat and here we go.
This is one and a half inches approximately thick so one and a half it's seven and a half inches
wide this way and it's 48 inches long. Now if I do by inches I have 540 cubic inches in here. If I
by foot there's 45. If I'm doing it by inches I'm going to divide by 144 there's 3.75 board foot
or if I did it by linear footage I'm going to divide by 12 so you get the same item. So for
there's three and three quarters board foot in here. One other thing you got to know when you
to buy lumber at a hardwood supplier they're going to sell you thicknesses above three quarter
in quarters. Everything's called quarters four quarter five quarter six quarter seven quarter
eight quarter and so forth and those are quarters of an inch. So when you have something like this
notice I notated that six quarter lumber and that's how it said six quarter not six fourths
six quarter that's approximately one and a half inches thick. So an eight quarter would be almost
two inches thick a four quarter would be just slightly under an inch and that's how it's all
called out and now that's how you multiply thickness times width times length in either
inches or foot. If it's in inches divide by 144. If it's in footage divide by 12 and now you know
what a board foot is. As you use this system ongoing it'll become second nature to you and
you'll start to see patterns that will develop. For instance a one by six is always half of a board
foot per linear foot. A two by six is one board foot per linear foot and so forth. There's patterns
like that and undoubtedly you yourselves have worked out some shortcuts for this those of the
you that use this system and if you have some insights you'd like to offer to your fellow viewers
won't you do so in the comments below and if you found this video to be helpful
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We look forward to talking to you until the next time this is Dirt Farmer Jay at DirtFarmerJay.com
