Firewood Cords Needed Calculator
Calculate how many cords of firewood you need to heat your home through winter based on climate, home size, stove efficiency, and wood species.
Cord vs face cord — the most-confused firewood term
A full cord (also called a “bush cord” or “true cord”) is a precisely defined volume:
4 ft wide × 4 ft tall × 8 ft long = 128 cubic feet of stacked wood
A face cord (also called a “rick” or “running cord”) is the same 4 × 8 ft face but only one log length deep, typically 16 inches:
4 ft × 8 ft × 1.33 ft (16") = 42.7 cubic feet = roughly 1/3 of a full cord
When buying firewood, always clarify which unit. A “$200 cord” might mean a true cord (great deal) or a face cord (overpriced 1/3 cord). Reputable sellers specify; some don’t.
Other related terms:
- Short cord / “Country cord”: 16" logs but volume varies; not standardized
- Stove cord: 16-18" lengths to fit standard stove openings
- Stacked cord: confirmed dimensions when stacked
- Loose cord: thrown into a truck bed; only ~75-80% of stacked volume
Heating value by species (BTU per cord)
Wood species vary dramatically in BTU output. The denser and harder the wood, the more BTU per cord. Air-dried (seasoned) values:
| Species | BTU/cord (millions) | Density |
|---|---|---|
| Hardwoods (high BTU) | ||
| Osage orange / Hedge | 32.9 | Very heavy |
| Hickory (shagbark) | 28.5 | Very heavy |
| White oak | 29.1 | Very heavy |
| Black locust | 27.9 | Heavy |
| Bur oak | 26.2 | Heavy |
| Beech | 27.5 | Heavy |
| Sugar maple | 24.0 | Heavy |
| Ash (white) | 23.6 | Medium-heavy |
| Red oak | 24.0 | Medium-heavy |
| Hop hornbeam (ironwood) | 27.1 | Very heavy |
| Apple | 27.0 | Heavy |
| Cherry | 19.6 | Medium |
| Yellow birch | 23.6 | Medium-heavy |
| Walnut (black) | 22.2 | Medium |
| Tamarack/larch | 21.8 | Medium (softwood) |
| Medium hardwoods | ||
| Red maple | 18.5 | Medium |
| Sycamore | 19.5 | Medium |
| Cottonwood | 16.1 | Light |
| Aspen | 14.7 | Light |
| Basswood | 13.8 | Light |
| Softwoods (lower BTU) | ||
| Tamarack/larch | 21.8 | Medium-high (best softwood) |
| Douglas fir | 20.7 | Medium |
| Yellow pine | 20.5 | Medium |
| Western red cedar | 18.2 | Medium |
| White pine | 14.3 | Light |
| Eastern red cedar | 13.0 | Light |
| Balsam fir | 14.3 | Light |
| Hemlock | 19.3 | Medium |
| Spruce | 15.9 | Medium |
A cord of white oak puts out roughly twice the heat of a cord of white pine. If you’re paying $200/cord for firewood, oak is dramatically cheaper per BTU than pine.
The seasoning requirement
Fresh-cut “green” wood has 30-60% moisture content. It produces:
- Far less heat (water absorbs energy as steam)
- More smoke and creosote
- Difficulty igniting
- Glass on chimney walls
- Risk of chimney fires
Properly seasoned wood is 20% moisture or less (some sources say under 15% for ideal burning). Seasoning timeframes:
| Species | Seasoning time |
|---|---|
| Pine, fir (softwoods) | 6-12 months |
| Birch, maple | 12-18 months |
| Oak, hickory (dense hardwoods) | 18-24 months |
| Apple, walnut | 12-24 months |
| Black locust | 18-30 months |
Stack technique matters: stacked on pallets above ground, with airflow gaps, covered on top only (not sides), in a sunny location. A neat stack seasons faster than a chaotic pile.
A moisture meter ($20-$40 at any hardware store) tells you when wood is ready. Stab the meter into a freshly-split face: under 20% reads green; 15-20% is ready; under 15% is excellent.
Climate-based heating needs
How much firewood you need depends on climate (heating degree days), home size, insulation, and stove efficiency.
| Climate zone | Annual heating need (BTU/sq ft) |
|---|---|
| Mild (Atlanta, San Francisco) | 20,000-30,000 |
| Moderate (Washington DC, Boston) | 35,000-45,000 |
| Cold (Minneapolis, Chicago) | 55,000-70,000 |
| Severe (Anchorage, Winnipeg) | 80,000-100,000 |
| Arctic (Fairbanks) | 100,000-150,000 |
A 1,800 sq ft well-insulated home in a moderate climate needs roughly: 1,800 × 40,000 = 72 million BTU per season
At 80% stove efficiency burning oak (24M BTU/cord effective heat output): 72 ÷ 24 = 3 cords per season
The same home in a cold climate (60,000 BTU/sq ft) needs: 1,800 × 60,000 = 108M BTU → 4.5 cords
Severe climate, poor insulation: 1,800 × 90,000 × 1.4 = 227M BTU → 9-10 cords
Stove efficiency — the biggest variable
| Heat source | Efficiency |
|---|---|
| Open fireplace (most are negative net heat!) | 10-20% (often a net heat loss) |
| Older airtight stove (pre-1988) | 40-55% |
| Catalytic/secondary combustion stove (older EPA) | 60-75% |
| Modern EPA-certified stove (2020+) | 75-87% |
| Masonry heater (Russian/Finnish style) | 80-90%+ |
| Outdoor wood boiler | 40-60% |
| Pellet stove | 78-92% |
| Wood-fired furnace (newer) | 70-85% |
| Rocket mass heater (DIY) | 85-95%+ (with proper construction) |
Switching from an open fireplace to a modern stove can cut wood usage by 75%. The same heat with 1/4 the wood — and far less smoke, creosote, and indoor air pollution.
Open fireplaces are notoriously inefficient because:
- They pull warm room air up the chimney (often losing more heat than they produce)
- Most heat goes up the flue, not into the room
- They cool the rest of the house during operation
- Indoor air quality suffers
Many fireplaces can be retrofitted with an insert stove (sealed combustion box) that converts them to 70-80% efficiency.
Wood cost vs alternative fuels
For a typical winter heating need (75M BTU effective heat output):
| Fuel | Cost per million BTU (delivered, useful) | Cost for 75M BTU |
|---|---|---|
| Mixed hardwood @ $200/cord (80% efficient stove) | $11 | $830 |
| Pellets @ $300/ton, 85% efficient stove | $19 | $1,420 |
| Natural gas @ $1.50/therm, 95% efficient | $16 | $1,200 |
| Propane @ $3/gal, 95% efficient | $39 | $2,900 |
| Heating oil @ $4/gal, 85% efficient | $34 | $2,550 |
| Electric resistance @ $0.16/kWh | $47 | $3,510 |
| Heat pump (cold climate, $0.16/kWh, COP 2.5) | $19 | $1,420 |
| Free firewood (you cut it yourself) | $0 + your labor | $0 |
Self-cut firewood from your own woodlot is by far the cheapest heating fuel — but it represents serious labor (cutting, splitting, hauling, stacking). Most figures price your labor at zero.
Seasoning storage
A 3-cord stack (4×4×24 ft) needs about 100 sq ft of ground. Rules:
- Bottom log should be off the ground (pallets, concrete blocks)
- Stack should have airflow gaps
- Top should be covered (tarp, metal roofing) but sides open
- Avoid stacking against the house (insect bridge, moisture issue)
- South-facing location dries fastest
Most homesteads have a multi-stack rotation:
- Stack A: this winter’s wood (already seasoned)
- Stack B: next winter’s wood (seasoning)
- Stack C: cutting now for 2-3 winters out
Splitting and processing
Wood splits easier when slightly green and easier when frozen. Tools:
- Maul (8 lb): primary tool for hand splitting
- Splitting axe (4-5 lb): better for smaller rounds
- Hydraulic splitter ($1,500-$3,000): essential for large volumes
- Splitting wedge + sledge: backup for tough rounds
A motivated person can split 1/3 cord of pre-cut rounds in a day by hand. With a splitter, a cord per hour is realistic.
Bottom line
A full cord = 128 cubic feet (4×4×8 ft); a face cord is about 1/3 of that. Hardwoods produce 2x the BTU of softwoods. Most homes use 3-5 cords per season; cold climates need more, mild climates less. Modern EPA stoves are 75-85% efficient; open fireplaces are often a net heat loss. Season wood 1-2+ years before burning. Properly stored self-cut wood is the cheapest heating fuel available.