Firewood Heat Value Calculator: Million BTU & Total kWh

Firewood is graded by how much heat a full cord releases, published in millions of BTU for well-seasoned wood at about 20% moisture. The calculator takes the chart value for the species you pick, multiplies by the number of cords, and reports the total two ways: in million BTU, the unit heating charts use, and in kilowatt-hours, which lets you compare wood against electric or heat-pump heat.

The spread between species is large. Dense hardwoods such as osage orange, hickory, and oak pack 24 to 33 million BTU per cord, while light softwoods like pine, cottonwood, and aspen deliver closer to 16 to 18. That means a cord of oak can carry nearly twice the heat of a cord of pine for the same stack size — which is why hardwood commands a higher price by the cord.

These are published averages, not guarantees. Actual output depends on how dry the wood is, how efficient the stove is, and how the fire is tended. Unseasoned wood wastes energy boiling off its own water, so even the best species underperforms until it has dried.