Cunits for Firewood Buyers (Volume Conversion)
A cunit is 100 cubic feet, but buyers must confirm whether that means stacked firewood or solid wood. A U.S. cord is 128 cubic feet of gross stacked space, so 1 cord equals 1.28 stacked-basis cunits. Measure the wood and compare units only after the seller states the same volume basis in writing.
A buyer who asks for a written unit definition before ordering can compare offers more fairly than one who relies on a price tag alone. I have seen how a familiar-sounding volume term can hide a key difference: one seller may count the air between stacked pieces, while another may refer to wood alone.
That distinction changes the quantity you are buying. A cunit is a volume measure, but the word by itself does not say how the wood is arranged or whether air spaces count. Use the steps below to clarify the quote, measure the load, and keep a record you can use next time.
Define the Cunit and Confirm the Measurement Basis
A cunit equals 100 cubic feet, or 2.831684659 cubic metres. The number is only useful for a firewood order once you know what those cubic feet describe. Ask whether the seller means 100 cubic feet of stacked firewood, including air gaps, or 100 cubic feet of solid wood.
The U.S. cord is a standard stack measuring 4 feet high by 4 feet deep by 8 feet long. Its total space is 128 cubic feet, including the gaps between pieces. It is not a measure of 128 cubic feet of solid wood.
That gives two useful conversions when both units refer to gross stacked volume:
| Stacked-volume quantity | Cunit equivalent | Cord equivalent |
|---|---|---|
| 1 cunit | 1.00 cunit | 0.78125 cord |
| 1 cord | 1.28 cunits | 1.00 cord |
| 100 ft³ | 1.00 cunit | 0.78125 cord |
| 128 ft³ | 1.28 cunits | 1.00 cord |
A cord’s solid-wood content varies with the size and shape of the pieces and how they are stacked. Short, crooked, or uneven pieces can leave a different amount of air space than uniform pieces. So do not treat the cord’s 128 cubic feet of gross space as solid wood.
Before paying, ask the seller to state in writing:
- What one cunit means in this sale.
- Whether the count is based on stacked volume or solid-wood volume.
- How the seller will measure the order, including whether it will be stacked or delivered loose.
- Whether the stated quantity applies before or after delivery.
Key takeaway: “One cunit” is not enough detail for a fair comparison. Get the basis and measurement method.
Measure and Convert a Firewood Stack
For a regularly stacked load, multiply its length by its average height and average depth to find gross cubic feet. Measure each dimension in feet. Divide that result by 100 for stacked-basis cunits, or by 128 for cord-equivalents. Use these conversions only when the measured space and the quoted unit share the same stacked-volume basis.
Take the measurements
Measure the wood as a stack, not as a guess based on the truck bed or the number of rows. A simple measuring tape and written notes are enough for a regular stack.
- Measure the stack’s length from end to end.
- Measure its height at several points if the top is uneven, then use a reasonable average.
- Measure the depth of the stack. If the depth varies, take several measurements and average them.
- Multiply length × average height × average depth.
- Divide cubic feet by 100 to get stacked-basis cunits, or by 128 to get cord-equivalents.
Example: A stack measures 16 feet long, averages 4 feet high, and is 2 feet deep. Its gross volume is 16 × 4 × 2 = 128 cubic feet. That equals 1.28 stacked-basis cunits, or one cord by gross stacked volume.
| Measured stack | Gross volume | Stacked-basis cunits | Cord-equivalents |
|---|---|---|---|
| 8 ft × 4 ft × 2 ft | 64 ft³ | 0.64 | 0.50 |
| 10 ft × 4 ft × 2.5 ft | 100 ft³ | 1.00 | 0.78125 |
| 16 ft × 4 ft × 2 ft | 128 ft³ | 1.28 | 1.00 |
These calculations describe the space occupied by a stack. They do not measure the solid wood inside it. If the seller quotes solid-wood cunits, the stacked conversion table does not apply. Ask for the seller’s method for measuring or estimating solid volume, then compare it with another offer only if that offer uses the same basis.
For loose firewood, measurements of the truck or pile do not automatically give a stacked volume. The pieces may settle, and empty space can vary. Ask how the seller defines and measures the quantity, and do not apply the cord conversion unless the seller’s unit is based on stacked volume.
Key takeaway: Measure length, average height, and average depth, then convert only on a matching basis.
Verify the Delivered Quantity and Resolve Discrepancies
Check the delivery against the unit definition on the order. For stacked wood, measure the delivered stack and calculate its gross volume. Compare that result with the invoice in the same unit. If the load is loose or irregular, first ask the seller how its quantity is defined; a stack formula cannot verify a solid-volume claim.
Worked delivery examples
These examples show how to check a transaction; they are not claims about a particular seller or delivery.
Example 1: A stacked-basis quote. A buyer orders 1 cunit, defined in writing as 100 cubic feet of stacked firewood. After stacking, the load measures 10 feet long, 4 feet high, and 2.5 feet deep. The measured volume is 100 cubic feet, or 1 stacked-basis cunit. The buyer has a direct comparison to the stated quantity.
Example 2: A cord quoted against cunits. A buyer is offered 1 cord, while another seller quotes 1.28 cunits. If both sellers define their units as gross stacked volume, the quantities are equivalent on paper: 128 cubic feet. The buyer should still check the actual stack and the terms of each offer.
Example 3: An undefined cunit. A seller quotes 1 cunit but will not say whether it is stacked or solid volume. The buyer should not assume it means 100 cubic feet of stacked firewood. Ask for a written definition before comparing the price or accepting the delivery.
If your measurement differs from the invoice, first check for a simple cause: an uneven stack, an inaccurate average, or a different measurement method. Write down the dimensions, photograph the stack with a tape measure in view, and keep the original quote and messages. Then ask the seller to explain the difference using the agreed basis.
Avoid claiming a shortfall from a measurement that does not match the seller’s stated method. For example, a loose load cannot be checked with the dimensions of a neatly stacked cord unless it is stacked or the seller has specified another agreed method. If the seller defined the order in writing but the measured amount does not match, share your measurements and ask how the quantity will be resolved.
Key takeaway: Compare the delivered amount with the written definition, not with an assumption about what “cunit” usually means.
Record Units, Basis, and Conversion for Future Orders
A useful firewood record includes the unit, its basis, the measurement method, and the quantity delivered. Keep the dimensions and conversion beside the price. This makes it easier to compare suppliers next season and helps prevent a stacked-volume quote from being confused with a solid-volume quote.
Compare prices on the same basis
For stacked-basis quotes, convert each offer to a shared unit before comparing prices. If a seller charges $240 per stacked-basis cunit, then 1.28 cunits, the gross stacked volume of one cord, would cost $307.20 at that rate. This is a simple unit comparison, not a judgment about wood quality, delivery, or other terms.
Do not use that calculation for solid-volume cunits. A price per solid-volume cunit cannot be converted to a cord using 128 cubic feet per cord, because 128 cubic feet is the cord’s gross stacked space, air gaps included. Get comparable prices using the same basis or request a clear conversion method from the seller.
For future orders, save:
- The seller’s written definition of a cunit.
- Whether the quantity is stacked or solid volume.
- The ordered quantity and price.
- The measurement method and any delivery terms.
- Your measured dimensions and calculated volume.
Key takeaway: A short written record turns next year’s price comparison into a like-for-like check.
Conclusion and Frequently Asked Questions
A cunit gives you a useful volume figure only when its basis is clear. For stacked firewood, 100 cubic feet equals one cunit, and 128 cubic feet equals one cord. State the basis, measure the stack, and keep the calculation with your order record. Never apply the stacked cord conversion to solid-wood volume.
What is a cunit of firewood?
A cunit is 100 cubic feet, or 2.831684659 cubic metres. Ask whether the seller means stacked volume or solid-wood volume.
How many cunits are in a cord?
On a gross stacked-volume basis, one U.S. cord is 128 cubic feet, or 1.28 cunits.
How many cords are in one cunit?
One stacked-basis cunit is 100 cubic feet, equal to 0.78125 cord by gross stacked volume.
Does a cord contain 128 cubic feet of solid wood?
No. A cord measures a stack 4 feet by 4 feet by 8 feet. Its 128 cubic feet includes the air spaces between pieces.
Can I convert a solid-volume cunit to cords?
Not with the standard 128-cubic-foot cord conversion. That conversion applies to gross stacked volume, not solid wood.
How do I measure a stacked firewood load?
Measure length, average height, and average depth in feet. Multiply the three measurements to get gross cubic feet.
How do I convert cubic feet to stacked-basis cunits?
Divide the gross stacked cubic feet by 100. For example, 100 cubic feet equals one stacked-basis cunit.
How do I convert cubic feet to cord-equivalents?
Divide gross stacked cubic feet by 128. Use this only when the measurement is stacked volume.
Can I measure loose firewood with the same method?
Not reliably as stacked volume. Ask the seller how the loose load is measured and what quantity basis appears on the order.
What should I do if a seller does not define “cunit”?
Ask for the definition in writing before buying. Confirm whether it means 100 cubic feet stacked or 100 cubic feet of solid wood.
(This article was written by one of our staff writers, Samuel Vance. Visit our Meet the Team page.)
