This cord of wood calculator exists because of one word: face cord. A full cord is a legally defined quantity — 128 cubic feet of stacked wood — and a face cord is not defined at all. It is whatever the seller's saw was set to that morning. Measure the stack you were delivered, enter what you paid, and this page tells you what fraction of a real cord you got and what that works out to per cord.
Arb Digital keeps a free tools library of everyday measurement and pricing maths, and this one is squarely in the price-comparison family: the arithmetic is trivial, the units are the problem. The tool measures stacked volume and converts it to cords and to a unit price. It does not identify species, judge moisture content or estimate heat output from a photograph.
What This Cord of Wood Calculator Does
Enter the length and height of the stack in feet, the length of the cut pieces in inches, and how many rows deep the stack is. The tool multiplies those into stacked cubic feet, divides by 128 to get full cords, and divides your total price by that to get the price per full cord — the only number that lets you compare two suppliers honestly.
The supporting figures give the raw cubic footage, the price per full cord, how many face cords the same wood represents at that piece length, and, if you tell it what the seller called the load, how the delivered stack compares with the claim.
One boundary worth stating: this page measures firewood specifically, in cords. If you want generic volume arithmetic, the cubic yard calculator handles bulk materials sold by the yard and the volume converter moves between cubic units. Neither of them knows what a cord is, and the cord is the entire difficulty here.
How to Use It
- Measure the stack after it is stacked, not on the truck. A loose pile has far more air in it, and no quantity can be determined from a dumped load.
- Measure the length and height in feet. Use the average if the stack is uneven, and measure to the top of the wood rather than the top of the highest piece.
- Measure the pieces. Take several and use the average. Piece length varies more than sellers admit and it scales the whole answer.
- Count the rows. One row deep is the common delivery. Three rows of 16-inch wood is what makes a full cord.
- Enter what you paid, including delivery. Then compare the price-per-full-cord figure against other quotes, converted the same way.
The Formula: What 128 Cubic Feet Means
A cord is defined by volume, not by weight or by piece count:
cubic feet = length (ft) × height (ft) × piece length (in) ÷ 12 × rows
cords = cubic feet ÷ 128
The classic picture of a cord is a stack 4 feet high, 4 feet deep and 8 feet long: 4 × 4 × 8 = 128. In practice nobody stacks 4 feet deep, so a cord arrives as a stack 4 feet high and 8 feet long, three rows of 16-inch wood deep.
Worked example. A stack 8 feet long, 4 feet high, one row deep, of 16-inch pieces. That is 8 × 4 × (16 ÷ 12) = 42.67 cubic feet, which is 42.67 ÷ 128 = 0.333 of a cord — one third. If you paid $250 for it, the price per full cord is 250 ÷ 0.333 = $750. Whether that is a good price depends on your local market, but you now have a number you can compare with a quote for "a cord delivered" instead of guessing.
The critical detail is the 128 includes air. The definition covers wood "ranked and well stowed", as the University of New Hampshire Extension guide to buying firewood puts it — meaning stacked neatly with the pieces parallel and touching. A carelessly thrown stack of the same wood occupies noticeably more space and contains less wood, which is why a seller who stacks it themselves may stack it loosely, and why you should measure after restacking if the load looks airy.
Face Cords, Ricks and Racks: Why This Is the Real Problem
A face cord is a stack 4 feet high and 8 feet long, one row deep. Its volume therefore depends entirely on how long the pieces are, and nothing else. At 12 inches it is 32 cubic feet, a quarter of a cord. At 16 inches it is 42.67 cubic feet, a third of a cord. At 24 inches it is 64 cubic feet, half a cord. Two sellers can both advertise "a face cord for $250" and one of them can be selling twice the wood.
The words rick, rack, truckload and pile are worse, because none of them describes a shape at all. In many US states this is not merely confusing but unlawful: New Hampshire's rule, quoted in the Extension guide above, is that firewood may only be sold by the cord or a fraction of a cord and never as a truckload, face cord, rack or pile. Similar method-of-sale requirements come from NIST Handbook 130, the uniform laws and regulations on legal metrology that states adopt, which covers how fireplace and stove wood must be sold and what has to appear on the delivery ticket.
The rules are not uniform, though, and enforcement varies enormously. Some states permit face-cord sales provided the piece length is disclosed; some require a written sales invoice stating the quantity in cords; some regulate little. Two practical defences work everywhere. Ask for the piece length before you buy, and convert every quote to a price per full cord — which is what the second figure in the grid above is for.
What Actually Determines How Long the Wood Lasts
Volume is what you buy, but it is not what you burn. Three other variables decide how far a cord goes, and none of them is on the delivery ticket.
Species is the biggest. A cord is a fixed volume, so a cord of dense hardwood contains far more wood substance — and therefore far more heat — than a cord of a light softwood at the same moisture content. Penn State Extension's analysis of whether wood heat pays off works in energy per cord for exactly this reason, and also accounts for appliance efficiency, which differs sharply between an open fireplace and a modern stove.
Moisture is the second. Freshly cut wood can be half water by weight, and burning it wastes energy boiling that water off, produces more creosote and gives less usable heat. Seasoned wood has been split, stacked off the ground and covered on top for long enough to dry. A green cord and a seasoned cord are the same volume and are not the same purchase.
Stacking quality is the third and is the one you can control at delivery. Neatly ranked wood in a measured stack is the basis of the entire cord definition; a jumbled heap of the same pieces looks like more wood and is not.
Comparing Firewood With Other Fuels
Because a cord is a volume of a variable material, comparing it with gas or electricity requires converting both to delivered heat, not to raw energy. Two adjustments matter: the energy content per cord for the species you are buying, and the efficiency of the appliance burning it. An open fireplace can deliver a small fraction of the fuel's energy into the room, while a modern certified stove delivers most of it.
Do that conversion before assuming wood is cheaper. The energy converter handles the unit side, the natural gas converter deals with therms and cubic feet, and the heat loss calculator estimates how much heat the building needs in the first place — which is usually a bigger lever than the fuel choice. For the pure price-per-unit comparison across suppliers, the unit price comparison calculator does the same job this page does for cords.
Arb Digital's free tools library covers measurement, energy and unit-price maths for the everyday decisions that turn on a definition, and our team is happy to talk through anything the tools cannot answer.
Browse Free Tools Talk to Arb DigitalCommon Mistakes to Avoid
- Comparing a face-cord price with a cord price — they are different quantities. Convert both to a price per full cord first.
- Measuring a dumped load — quantity cannot be determined from a pile. Stack it, then measure the stack.
- Assuming the piece length — measure several pieces and average them. An inch or two changes the volume by several per cent.
- Leaving delivery out of the price — a lower wood price with a high delivery fee often loses to the opposite.
- Treating green and seasoned wood as the same purchase — the same volume of unseasoned wood delivers less heat and more creosote.
Related Free Tools From Arb Digital
Use the cubic yard calculator for bulk materials sold by the yard, the volume converter for cubic unit conversion, the energy converter when comparing fuels, the heat loss calculator to size the heating need itself, and the unit price comparison calculator whenever two sellers quote in different units. Everything else is in the free online tools hub.
Frequently Asked Questions
128 cubic feet of stacked wood. The classic shape is 4 feet high by 4 feet deep by 8 feet long, but any stack whose length, height and piece length multiply to 128 cubic feet is a cord.
No. A face cord is 4 feet by 8 feet by whatever the piece length is, so its volume varies. At 16-inch pieces it is one third of a cord; at 24-inch pieces it is half a cord. The term has no fixed definition.
It depends on the jurisdiction. Some states require firewood to be sold only by the cord or a fraction of a cord and prohibit terms like face cord, rick, rack and truckload, while others allow them if the piece length is disclosed. Check the rule where you live.
Divide 48 by the piece length in inches. Twelve-inch pieces give four face cords, 16-inch pieces give three, and 24-inch pieces give two.
Not reliably. A loose pile contains far more air than a ranked stack, and the cord definition assumes the wood is stacked neatly with the pieces parallel and touching. Stack it first, then measure.
Because a cord is a volume, not an amount of fuel. Dense hardwood packs far more wood substance into the same 128 cubic feet than light softwood, and unseasoned wood spends energy boiling off its own water.
Uniform method-of-sale rules generally require the quantity in cords or fractions of a cord along with the seller's details. If the ticket says one load and nothing else, you have no measurable basis for the price.
This tool measures stacked volume from the figures you enter and converts them to cords and a unit price. Firewood method-of-sale rules differ by state, province and country, and the regulations of your own jurisdiction govern any dispute with a seller.
