Off Grid Living WisdomFirewood Calculator
This free firewood calculator shows how many cords of wood you need to heat your home, based on last winter's propane, oil, gas or electric bill. Pick your wood species and stove, and it estimates the cords to stack, the cost per year and how much you could save by heating with wood.
How the firewood calculator works
It turns last winter's heating fuel into the heat your house actually used, then works out how many cords of your firewood deliver the same heat in your stove. The math uses standard energy values: propane 91,500 BTU per gallon, heating oil 138,500, natural gas 100,000 per therm, electricity 3,412 per kWh.
How many cords of wood do I need? Rule of thumb
| Home (reasonably insulated) | Mild winter | Cold winter | Very cold |
|---|---|---|---|
| Cabin, under 1,000 sq ft | 1–2 cords | 2–3 cords | 3–4 cords |
| 1,000–2,000 sq ft | 2–3 cords | 3–5 cords | 5–7 cords |
| 2,000–3,000 sq ft | 3–4 cords | 5–7 cords | 7–10 cords |
Whole-house heat with an EPA-certified stove and mixed hardwood. Drafty older homes can burn 30–50% more.
What counts as a cord
A full cord is 4 feet high, 8 feet long and 4 feet deep: 128 cubic feet of stacked wood (about 3.6 cubic meters). A "face cord" or "rick" is one log-length deep, often a third of a cord, so always ask for the dimensions. Prices run roughly $150–$500 per cord delivered, more in cities and late winter.
Dry wood is half the battle
Wood must be under 20% moisture to burn clean. Wet wood wastes heat boiling off water and coats the chimney with creosote. Split, stack off the ground in single rows, cover the top only, and give it 6–24 months depending on species. Check with a $30 moisture meter on a freshly split face.
Burn less wood for the same heat: stove choice, burning method and chimney care.
105 pages, 7 calculators, a fill-in family plan and checklists. $47, instant download.
Frequently asked questions
How many cords of wood do I need for winter?
Most homes heated fully with wood burn 3–5 cords in a cold winter, and 5–7 or more in very cold climates. Use the calculator with last year's fuel bill for your own number, and keep a 25% reserve.
Is heating with wood cheaper than propane?
Usually, if you can buy wood at $150–$350 a cord. In the calculator's example, a home that spent $2,400 on propane would spend about $1,140 on firewood, saving about $1,260 a year. Your result depends on local prices.
Which firewood gives the most heat?
Dense hardwoods: Osage orange, hickory, black locust and oak give 24–33 million BTU per cord. Pine, aspen and cottonwood give 15–17, about half as much per cord.
How much is a cord of wood?
Roughly $150–$500 per cord delivered in the US, depending on region, species and season. Buying in spring or summer is cheapest and gives the wood time to dry.