Firewood Calculator

• How to Use the Firewood Calculator
• Worked Example: A Stack of Red Oak
• What Is a Cord of Wood?
• Cord vs Face Cord vs Rick
• How Much Does a Cord of Firewood Weigh?
• Heat Content by Species
• How Much Firewood Do You Need for Winter?
• Buying Firewood Without Getting Shorted
• FAQs

In fact, firewood is sold by volume, but it is delivered as a messy pile of logs — and that gap is exactly where buyers lose money. A load advertised as a cord might be a true 128 cubic feet of stacked wood. It might be far less once you stack it neatly and measure it. This firewood calculator turns your stack’s length, height, and log length into cords, face cords, estimated weight, and heat content, so you can check any pile in about a minute. Whether you are measuring a delivered load before you pay, working out how much storage space a winter supply needs, or comparing the heat in oak against pine, the numbers below give you a fair, standard measure that both buyer and seller can agree on.

How to Use the Firewood Calculator

In practice, measure the stack, not the pile. Loose-thrown wood contains far more air than stacked wood, so stack the logs neatly in rows first, then take three measurements. Next, enter the stack length in feet, the stack height in feet, and the length of the logs in inches. If your wood rack holds more than one row front to back, enter the number of rows.

Then pick the species. The seasoned weight and heat content of a cord change a lot between a dense hardwood like oak and a light softwood like pine. In fact, the calculator returns the stack volume in cubic feet, the amount in full cords, the amount in face cords at your log length, the estimated seasoned weight, and the heat the wood will give off in million BTU. Every figure assumes the wood is seasoned (air-dried); green wood of the same volume can weigh 40 percent or more extra because of the water inside it.

Worked Example: A Stack of Red Oak

For example, say you have one row of red oak stacked 8 feet long and 4 feet high, with logs cut to 16 inches. Next, enter 8 for the length, 4 for the height, 16 for the log length, 1 row, and red oak as the species. The firewood calculator works through it like this:

So a single neat row along an 8-foot rack is exactly one face cord, one third of a full cord, a little over half a ton of seasoned red oak, and roughly 8.2 million BTU of heat. That is about the same energy as 59 gallons of heating oil. If a seller delivers this amount and calls it a full cord, the calculator shows the shortfall straight away: you received one third of what you paid for.

What Is a Cord of Wood?

A cord is the legal standard unit for firewood in the United States: 128 cubic feet of stacked wood, bark, and air gaps combined. The classic arrangement is a stack 4 feet high, 4 feet deep, and 8 feet long, but any shape that multiplies out to 128 cubic feet is a full cord. The definition comes from the model weights-and-measures rules published in NIST Handbook 130, which most states have adopted, so in most states firewood must be sold by the cord or by a stated fraction of a cord.

Inside those 128 cubic feet, only about 80 to 90 cubic feet is solid wood. The rest is the air between the logs, which is why tight, straight stacking matters and why a loose pile always measures smaller once it is stacked properly. In short, anything sold as a “truckload,” a “pile,” or a “rack” without a cord measurement is not a standard unit at all, and the only way to know what you got is to stack it and run the numbers.

Cord vs Face Cord vs Rick

In fact, sellers use several smaller units, and confusing them is the most common way buyers overpay. A face cord is a stack with a face 4 feet high and 8 feet long, but only one log deep. Its volume therefore depends entirely on the log length:

A rick is not a fixed measure at all. In many regions it simply means a face cord, but the log length behind it varies, so treat the word as a warning to ask for dimensions. The same applies to a “stove cord” or “furnace cord.” None of these are dishonest units when the dimensions are stated honestly; the problem is only the price comparison. In fact, a face cord of 16-inch logs at $150 sounds cheaper than a full cord at $400, but it is one third of the wood, so the full cord is the better buy. Finally, convert every quote to a price per full cord before you compare, and this calculator does the conversion for you.

How Much Does a Cord of Firewood Weigh?

Weight matters when you haul wood yourself, because a full cord of seasoned hardwood can weigh far more than a half-ton pickup can legally carry. The figures below are for air-dried (seasoned) wood from Utah State University Extension’s wood heating data, with a similar table published by Oklahoma Cooperative Extension:

In fact, a cord of seasoned red oak at 3,528 pounds is two or three trips in a typical half-ton truck once you respect the payload rating, and green wood is heavier still. As a result, if a price includes delivery, that weight is the seller’s problem — but it explains why delivered cords cost what they do, and why “free delivery” loads that arrive suspiciously light deserve a careful measure.

Heat Content by Species

Overall, a cord is a volume measure, not an energy measure, and the table above shows why species is the biggest variable in firewood value. Dense hardwoods pack more wood fiber — and therefore more stored energy — into the same 128 cubic feet. A cord of Osage orange holds about 32.9 million BTU, roughly double the 16.2 million BTU in a cord of ponderosa pine. That does not make pine bad firewood: it lights easily, seasons fast, and is ideal for kindling and for spring and fall fires when you want quick warmth rather than an all-night burn.

It does mean a cheap cord of pine is not automatically a bargain next to a pricier cord of oak. To compare fairly, divide the price by the million BTU per cord. At $300, red oak works out to about $12.20 per million BTU; pine would have to fall to about $198 a cord to match it. In fact, the calculator’s heat figure also helps wood-stove owners sanity-check their winter. If your home used about 500 gallons of heating oil last year, that is roughly 69 million BTU. That is about 2.8 cords of seasoned red oak before allowing for the difference in stove efficiency.

How Much Firewood Do You Need for Winter?

In fact, how long a cord lasts depends on your stove, your climate, and whether wood is your main heat or a supplement. As a rough guide, a home heated only by an efficient modern wood stove in a cold climate typically burns three to five cords across a winter. A home that burns wood in the evenings and at weekends to take the edge off a furnace bill might use one to two cords. An occasional fireplace used for atmosphere may not finish a single face cord in a season.

Open fireplaces are the least efficient way to burn wood, sending most of the heat up the chimney, so fireplace users burn more volume for the same comfort. In short, whatever your pattern, buy seasoned wood if you plan to burn it this year: green wood needs six to twelve months of drying for most species, and oak can need longer.

Wood is seasoned when its moisture content falls to about 20 percent or below — the ends of the logs look gray and checked with cracks, the bark loosens, two pieces knocked together sound hollow rather than dull, and a moisture meter (an inexpensive tool) confirms the reading on a freshly split face. And while you are planning for the cold months, our snow load calculator shows what the same season’s snow weighs on your roof, and the hot tub calculator covers the other backyard fixture that gets surprisingly heavy when it is filled.

Buying Firewood Without Getting Shorted

In fact, a few habits protect you on every purchase. Buy by the cord or a stated fraction of one, and agree the species, the log length, and whether the wood is seasoned before delivery day. When the load arrives, stack it before the driver leaves if you can, measure the stack with a tape, and run it through this calculator while the seller is still there. As a result, disagreements are easy to settle with a tape measure and hard to settle a week later. Finally, ask for a receipt that states the amount in cords; many states require one.

In fact, store the wood off the ground, covered on top but open at the sides so air can move through it, and keep it a few feet from the house wall. Finally, buy local. For example, moving firewood long distances spreads invasive pests such as the emerald ash borer, and many states and campgrounds restrict or ban firewood brought in from outside the area — another reason the cheapest cord two counties away may not be the bargain it looks.

FAQs

How many cubic feet are in a cord of wood?

A full cord is 128 cubic feet of stacked wood, including the bark and the air gaps between logs. The standard arrangement is a stack 4 feet high, 4 feet deep, and 8 feet long. As a result, of that volume, roughly 80 to 90 cubic feet is solid wood and the rest is air, which is why neatly stacked wood always measures honestly and loose piles do not.

Is a face cord the same as a cord?

No. In fact, a face cord is a stack 4 feet high and 8 feet long but only one log deep, so its volume depends on the log length. With the common 16-inch log length, a face cord is 42.67 cubic feet — exactly one third of a full cord. Finally, always convert face cords to full cords before comparing prices between sellers.

How much does a cord of firewood weigh?

In fact, a seasoned cord weighs from about 2,300 pounds for a light softwood like ponderosa pine to about 4,700 pounds for a dense hardwood like Osage orange. Red oak, one of the most common firewoods, weighs about 3,528 pounds seasoned. Green wood weighs considerably more — often 40 percent or more — because of the water still inside it.

How long will a cord of wood last?

It depends on how you heat. For example, a home relying on an efficient wood stove as its main heat source in a cold climate usually burns three to five cords a winter, so one cord lasts roughly a month to six weeks of full-time heating. Evening-and-weekend burners stretch a cord much further, and an occasional fireplace may use only a face cord in a whole season.

What is the best firewood to burn?

Overall, dense, seasoned hardwoods give the most heat per cord: Osage orange, oak, and sugar maple lead the list, with white ash close behind and prized because it splits easily and seasons quickly. In contrast, softwoods like pine hold about half the heat per cord but light easily and dry fast, which makes them good kindling and shoulder-season wood. Whatever the species, dry wood at 20 percent moisture or below matters more than the tree it came from.

How can I check that I received a full cord?

Stack the wood neatly in rows, then measure the stack’s length and height in feet and the log length in inches. Next, enter the three numbers in the firewood calculator on this page. If the result is well under the amount you paid for — say you ordered a cord and measure 0.7 — contact the seller with your measurements. In most states firewood must legally be sold by the cord or a stated fraction of one.

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