About the Firewood Calculator
This firewood calculator turns the dimensions of a woodpile into full cords, face cords (ricks) and cubic feet, then estimates how much heat the wood holds based on its species. Enter the stack length and height, the length of the individual pieces, the wood type and the price you paid or were quoted.
It is useful when buying firewood — sellers use "cord", "face cord", "rick" and "truckload" loosely, and the price per cord only means something once you know how much wood you actually got. It also helps wood-stove owners compare species: a cord of hickory holds nearly twice the heat of a cord of poplar, so the cheaper wood is not always the better deal.
Heat values assume seasoned, air-dried wood at about 20% moisture. Green wood holds far less usable heat because energy is spent boiling off water. A face cord here is a 4 × 8 ft stack of 16-inch pieces (one-third of a full cord), the most common definition in the US.
With the default inputs, the full cords is 0.333. Change any value above to recalculate instantly.
How to use the firewood calculator
- 1Measure the length and height of the stacked woodpile in feet.
- 2Measure the length of a typical split piece in inches (usually 16).
- 3Choose the wood species that makes up most of the pile.
- 4Enter the price per full cord and your stove or fireplace efficiency.
- 5Read the cords, face cords and heat value, and use the chart to compare species.
Formula and method
A full cord is a tightly stacked pile measuring 4 ft high, 4 ft deep and 8 ft long — 128 cubic feet including the air gaps between logs. The calculator multiplies stack length, height and piece length (converted from inches to feet) to get the stacked volume, then divides by 128. A face cord is a 4 × 8 ft face of 16-inch pieces, or 42.67 cubic feet — one-third of a full cord.
Heat content uses typical values for air-dried wood (about 20% moisture) in million BTU per full cord. Multiplying by your appliance efficiency gives the heat that actually reaches your home, and dividing the cord price by that useful heat gives a cost per million BTU you can compare with gas, oil or electric heating.
- L, H
- Stack length and height in feet
- piece
- Length of each split piece (stack depth) in inches
- BTU/cord
- Heat content of one full cord of the chosen wood, million BTU
- efficiency
- Share of the wood’s heat your stove or fireplace delivers to the room
Worked examples
A standard face cord of oak
An 8 ft long, 4 ft high stack of 16-inch oak holds 42.67 cubic feet — one face cord, or one-third of a full cord. At 24.6 million BTU per cord that is 8.2 million BTU, of which a 70% efficient stove delivers 5.74 million. At $300 per full cord this stack is worth $100.
A full cord of hickory
An 8 × 4 ft stack with 4-ft pieces is exactly 128 cubic feet, one full cord or three face cords of 16-inch wood. Hickory holds about 27.7 million BTU per cord; at 75% efficiency you get 20.8 million BTU, costing about $16.85 per million BTU at $350 a cord.
Long pile of pine at a lower price
A 20 × 5 ft stack of 18-inch pine is 150 cubic feet, or 1.17 full cords. Pine holds only about 15.9 million BTU per cord, so even at $200 a cord the heat costs about $20.96 per million BTU at 60% efficiency — more than the pricier hardwoods above.
Frequently asked questions
What is the difference between a cord and a face cord?+
A full cord is 4 ft high × 4 ft deep × 8 ft long, or 128 cubic feet. A face cord (also called a rick) is 4 ft high × 8 ft long but only one piece deep — with 16-inch pieces that is one-third of a full cord.
How much does a cord of firewood weigh?+
It depends on species and moisture. A cord of seasoned hardwood such as oak usually weighs roughly 3,500–4,500 pounds, while softwoods like pine are closer to 2,000–2,500 pounds; green wood is much heavier.
Which firewood burns hottest?+
Dense hardwoods hold the most heat per cord: hickory, oak, beech and sugar maple are at the top. Softwoods such as pine, spruce and poplar hold less heat per cord and burn faster, though they light easily and are fine for kindling or shoulder seasons.
How many cords of wood do I need for a winter?+
Divide your seasonal heating need in million BTU by the useful heat per cord. A home needing 40 million BTU with a 70%-efficient stove burning oak (about 17 useful M BTU per cord) would need roughly 2.3 full cords.
Does moisture content matter?+
Yes. Wood should be seasoned to about 20% moisture or less. Wet wood wastes energy evaporating water, burns cooler and creates more creosote, so the heat values in this calculator assume properly seasoned wood.
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