Firewood cord calculator

What is a firewood calculator?

A firewood calculator tells you how much wood is in a neatly stacked pile and expresses it in cords — the customary unit firewood is sold by. You measure the three dimensions of the stack (how long it is, how high it is, and how deep it is front to back), and the calculator multiplies them into a stacked volume and divides that volume by the size of one cord. The answer tells you whether the load you are buying, selling, or burning through the winter is a full cord, a half, or some other fraction.

The reason a calculator helps is that firewood is almost never sold as a tidy 1-cord block. Dealers advertise “a truckload”, “a face cord”, “a rick”, or “a rack”, and those words mean different amounts in different places. The one measurement that does not drift is the volume of the neatly stacked wood, so pricing and comparing loads always comes back to the cord.

What is a cord?

A cord is a stack of firewood measuring 4 feet high, 4 feet deep, and 8 feet long — 128 cubic feet of wood, air, and bark taken together. That volume is fixed by definition and is the figure the calculator divides by.

The confusing part is that most people do not burn 4-foot logs. Stoves and fireplaces take pieces 16 to 24 inches long, so wood is usually stacked just one log deep. A single 4 ft × 8 ft face of 16-inch logs is a face cord (also called a rick or a rack): it looks like a “cord” from the front but is only one third as deep, so it holds about one third of a cord. Because “face cord” is not a legally standardised amount, the honest way to compare two loads is to stack them, measure the length, height and depth, and let the volume speak — which is exactly what this calculator does.

How does the calculator work?

Stack the wood so the pieces lie roughly parallel and the gaps are as small as ordinary splitting allows, then measure:

• Stack length — how far the pile runs.
• Stack height — how tall it is.
• Stack depth (log length) — how deep it is front to back, which for a single-deep stack is just the length of the logs.

Each dimension has its own unit selector, so you can measure in feet, metres, inches or centimetres and mix them freely — the calculator converts everything internally. It then shows two results:

• Stacked volume, switchable between ft³ and m³.
• Cords, the stacked volume divided by 128 ft³.

Formulas

The stacked volume is length times height times depth. With length $L$, height $H$ and depth $D$:

$$V = L \times H \times D$$

The number of cords is the stacked volume in cubic feet divided by 128 ft³, the volume of one cord:

$$C = \frac{V}{128}$$

If you measured in metres, convert the volume to cubic feet first (or read the volume output in ft³):

$$V_{\text{ft}^3} = V_{\text{m}^3} \div 0.0283168$$

Worked examples

Example 1: a full cord

A stack is 8 ft long, 4 ft high, and 4 ft deep — the textbook cord:

$$V = 8 \times 4 \times 4 = 128 \, \text{ft}^3$$ $$C = \frac{128}{128} = 1 \, \text{cord}$$

So the stack is exactly one cord. Measured in metric, the same pile is 2.4384 m × 1.2192 m × 1.2192 m, which is still 128 ft³ (about 3.6245 m³) and still one cord.

Example 2: a face cord of 16-inch logs

A stack has a full 8 ft × 2 ft face but is only one 16-inch log deep. Entering the depth as 16 in:

$$V = 8 \times 2 \times \tfrac{16}{12} = 21.33 \, \text{ft}^3$$ $$C = \frac{21.33}{128} = 0.1667 \, \text{cord}$$

That is 0.1667 cord — one sixth of a cord for this short 2 ft face, and a reminder that a “face cord” depends entirely on how deep the logs are. Priced against a full cord, this load should cost about a sixth as much.

Example 3: a two-cord load

A delivery stacks up 8 ft long, 4 ft high, and 8 ft deep:

$$V = 8 \times 4 \times 8 = 256 \, \text{ft}^3$$ $$C = \frac{256}{128} = 2 \, \text{cords}$$

So the load is 2 cords — a common size for a small truck delivery.

Practical notes

• Stack it before you measure. A cord is defined for stacked wood. A heaped, thrown, or “loose” pile of the same weight of wood measures much larger because of the air between the pieces — a loose throw of one cord can occupy 180 ft³ or more. Always measure a neat stack.
• Ask what “cord” the seller means. If a price is quoted per “cord”, confirm it is a full 128 ft³ and not a face cord, rick, or rack. Measure on delivery: length × height × depth, then compare to 128 ft³.
• Depth is the log length. For the usual single-deep stack, the “stack depth” is simply how long the logs are — 16, 20, or 24 inches. Longer logs make a deeper stack and more wood for the same visible face.
• A cord is volume, not weight. How much heat a cord gives depends on the species and how dry it is: seasoned oak or hickory weighs far more and burns far longer than the same cord of pine or poplar. The calculator measures the space the wood fills, not its energy content.
• Same measurements, other jobs. If you are working out materials for the yard around the woodpile, the mulch calculator, the soil calculator, and the gravel calculator take the same length, width and depth and return the volume you need.