Cord of Wood Converter
Free Cord wood tool for home economics. Enter your details to get instant, tailored results and guidance. Includes formulas and worked examples.
Formula
Cords = (Length x Height x Depth) / 128
A full cord equals 128 cubic feet (4 ft x 4 ft x 8 ft). Multiply your stack dimensions in feet to get cubic feet, then divide by 128 to get the number of cords. A face cord is typically 1/3 of a full cord with 16-inch log lengths.
Worked Examples
Example 1: Standard Cord Verification
Problem: A firewood seller offers a stack of oak that is 8 feet long, 4 feet high, and 4 feet deep for $300. Is this a full cord and what is the energy value?
Solution: Volume: 8 x 4 x 4 = 128 cubic feet\nFull cord = 128 cubic feet, so this is exactly 1.000 cord\nOak BTU output: 1.0 x 24,000,000 = 24,000,000 BTUs (24.0 million)\nOil equivalent: 24,000,000 / 138,500 = 173.3 gallons\nGas equivalent: 24,000,000 / 100,000 = 240.0 therms\nCost per million BTU: $300 / 24 = $12.50
Result: Full Cord: Yes (128 cu ft) | 24.0M BTUs | Equals 173 gal oil or 240 therms gas
Example 2: Face Cord Price Comparison
Problem: A seller offers a face cord (8 ft long, 4 ft high, 16 inch logs) of maple for $150. What is the equivalent full-cord price?
Solution: Volume: 8 x 4 x 1.333 = 42.67 cubic feet\nCords: 42.67 / 128 = 0.333 cords (one-third)\nEquivalent full cord price: $150 / 0.333 = $450 per full cord\nThis is significantly more expensive than buying a full cord at typical $250-350 prices
Result: Face Cord = 0.333 full cords | Equivalent: $450/cord | Overpriced vs. $300 full cord
Frequently Asked Questions
What exactly is a cord of wood?
A cord of wood is a standard unit of measurement for firewood defined as a neatly stacked pile measuring 4 feet wide, 4 feet high, and 8 feet long, totaling 128 cubic feet. However, because logs are irregular and cannot pack perfectly, the actual solid wood content is approximately 80 to 90 cubic feet with the remainder being air space between logs. The cord measurement assumes wood is stacked tightly and uniformly without excessive gaps. This standard has been legally defined in most U.S. states and Canadian provinces to protect consumers from being shorted on firewood purchases. A cord is approximately 2 to 3 pickup truck loads depending on the truck bed size.
What is a face cord and how does it differ from a full cord?
A face cord, also called a rick or stove cord, is a stack of wood that is 4 feet high and 8 feet long but only as deep as the cut length of the logs, typically 16 inches instead of the full 4 feet deep of a standard cord. This means a face cord of 16-inch logs is one-third of a full cord, containing roughly 42.67 cubic feet versus 128 cubic feet. The term face cord is not a legally standardized measurement and can be misleading. Some sellers use it to charge disproportionately high prices compared to a full cord. Always ask for the dimensions and calculate the cubic footage to ensure you are getting a fair price per volume of wood.
How many BTUs does a cord of wood produce?
BTU output per cord varies by species and is directly related to wood density. Hickory produces the most heat at approximately 26.5 million BTUs per cord, making it the premium firewood choice. Oak (both red and white) produces about 24 million BTUs per cord and is the most popular firewood in the eastern United States. Hard maple produces about 24 million BTUs per cord as well. Birch generates roughly 20.8 million BTUs. Pine produces only about 17.1 million BTUs per cord but ignites easily, making it good for kindling. For comparison, one cord of oak provides roughly the same heat as 173 gallons of heating oil or 240 therms of natural gas.
How much does a cord of wood cost?
Cord prices vary significantly by region, season, wood species, and whether the wood is delivered and stacked. National average prices typically range from $150 to $400 per cord for mixed hardwoods. In the Northeast and Pacific Northwest, premium hardwoods like oak and maple can cost $300 to $500 per cord delivered. In the Southeast and rural Midwest, prices are often lower at $150 to $250 per cord. Prices are generally lowest in spring and summer when demand is low and highest in late fall and winter. Buying green wood and seasoning it yourself saves 20% to 40% compared to buying seasoned wood. Always price wood by the full cord rather than by face cord or truckload to make accurate comparisons.
How many cords of wood do I need for a winter?
Average consumption depends on your heating needs, climate, home insulation, and how you use your fireplace or stove. A home primarily heated with a high-efficiency wood stove in a cold northern climate typically burns 4 to 6 cords per season. An energy-efficient home using a wood stove as supplemental heat might use 2 to 3 cords per winter. Using a standard open fireplace for ambiance a few evenings per week might consume only 1 to 2 cords per season. Open fireplaces are about 10% to 15% efficient while modern wood stoves achieve 70% to 80% efficiency, meaning you need far less wood with a stove. Calculate your needs based on past usage or estimate based on your heating zone and equipment efficiency.
How do I compare wood heating costs to oil and gas?
To compare costs, calculate the cost per million BTUs for each fuel type. For wood, divide the price per cord by the BTU output in millions. For example, oak at $300 per cord produces 24 million BTUs, so the cost is $300 / 24 = $12.50 per million BTUs. For heating oil at $3.50 per gallon (138,500 BTUs per gallon), the cost is $3.50 / 0.1385 = $25.27 per million BTUs. For natural gas at $1.50 per therm (100,000 BTUs per therm), the cost is $1.50 / 0.1 = $15.00 per million BTUs. Adjust these calculations by your equipment efficiency, as a 75% efficient wood stove effectively costs $12.50 / 0.75 = $16.67 per million BTUs of actual delivered heat.