Firewood BTU & Wood Stove Cord Consumption Calculator
Calculate heat energy output (Million BTUs per cord) across 12 hardwood and softwood species, deduct moisture energy penalties (green vs seasoned wood), and calculate cords needed for winter heating with wood stove EPA efficiency.
Firewood Species & Moisture Content
EPA 2020 certified: 70%–80%; Older stove: 50%–60%
Million BTUs (MMBtu) per winter (~50–80 MMBtu typical)
100% for primary heat; 30%–50% for supplemental
Winter Firewood Cords Required
Properly Seasoned
3.7 Cords
Standard cords (128 cu ft stacked: 4ft × 4ft × 8ft)
Net Usable Heat per Cord
17.6 MMBtu / cord
From 24.4 MMBtu available (72% stove efficiency)
Moisture Evaporation Heat Penalty
-7.6% Energy Loss
2.0 MMBtu lost boiling water out of wood
Seasonal Economics & Fuel Equivalence
Total Seasonal Wood Cost:
$1,110.00 / winter
Heating Oil Equivalent per Cord:
~148 Gallons #2 Fuel Oil
Propane Equivalent per Cord:
~225 Gallons Propane
Frequently Asked Questions
What is the difference between a full cord and a face cord?
A full standard cord is a stack measuring 4 feet high, 4 feet deep, and 8 feet long (128 cubic feet). A face cord (or rick) is 4 feet high and 8 feet long, but only one log deep (typically 16 inches). A face cord is exactly one-third (1/3) of a full cord.
How can I tell if firewood is seasoned below 20%?
Use a digital pin-type wood moisture meter on a freshly split cross-section. Seasoned wood will show dark radial check cracks on the log ends, feel light, and make a resonant hollow "clack" when struck together rather than a dull thud.