How the firewood estimate works
The calculator starts from a rough planning baseline — a primary-wood-heat home in a moderate climate burns on the order of one full cord of seasoned dense hardwood per 600–700 sq ft per season with a modern stove (Oklahoma State's published range is one to two cords per 1,000 sq ft, and real homes land all over it) — then adjusts with our planning multipliers for climate, insulation, how much of your heat comes from wood, appliance efficiency (baseline ÷ your appliance's efficiency), and wood species. The climate and insulation factors are internal planning assumptions, not published constants, which is why results display as a wide range rather than a precise number.
Cord math, once and for all
| Term | Stack size | Fraction of a full cord |
|---|---|---|
| Full cord | 4' × 4' × 8' (128 cu ft) | 1 |
| Face cord / rick (16") | 4' × 8' × 16" deep | ~1/3 |
| Face cord (12") | 4' × 8' × 12" deep | 1/4 |
| Face cord (24") | 4' × 8' × 24" deep | 1/2 |
| "Truckload" | varies wildly | ask for dimensions! |
When buying, always convert the seller's unit to full cords to compare prices — a "$120 rick" of 16-inch wood is $360/cord.
Approximate heat content by species (per seasoned cord)
| Species | Million BTU/cord |
|---|---|
| Hickory, oak (white) | 26–28 |
| Hard maple, ash, red oak | 22–25 |
| Birch, elm, soft maple | 19–22 |
| Pine, spruce, fir | 14–17 |
| Cottonwood, willow, basswood | 12–14 |
Frequently asked questions
How long does a cord of wood last? It depends so heavily on your home, stove, weather, and wood that any fixed answer misleads — divide your seasonal estimate above by the length of your burning season instead. (A home burning 4 cords over a 5-month season averages about 3 weeks per cord in the cold months.)
Is it cheaper to heat with wood? Usually yes if you cut your own; often break-even if you buy seasoned hardwood at market prices — the win is resilience and taking the edge off a propane or electric bill.
Sources
- University extension firewood guides (heat values & cord definitions, e.g., Utah State, Penn State)
- U.S. state weights-and-measures cord definitions (128 cu ft)