Firewood Calculator
Find how many cords of firewood your house needs for a winter, in full cords and face cords, from its size, your climate and what you burn it in.
How much wood a winter takes comes down to three things: how much heat your house needs, how much of it the wood provides, and what you burn it in. The same cord gives about seven times the heat in a modern stove as in an open fireplace.
Your house
The space the stove or fireplace actually keeps warm. The whole house if wood heats it all; just the main floor or one room if that's what it reaches.
Square feet the wood heats
Your winters
How much of your heat is wood?
The furnace or heat pump covers whatever the wood doesn't.
Your wood and your stove
Denser wood packs more heat into every cord, and a newer stove gets more of it into the room.
What you burn
What you burn it in
Firewood for the winter
About 3 cords
To heat 1,500 sq ft with hardwood in a wood stove
A cord is a stack of split logs 4 feet high, 4 feet deep and 8 feet long. This assumes dry, seasoned wood; wet wood burns through more. 2026 figures.
💡About this calculator▼
Most people buy firewood by feel: two cords because that's what last year's pile looked like, or four because a neighbor said so. Then February comes and the pile is either gone or barely touched. How much wood a winter takes can be worked out from a few things you already know.
This works it out. Enter the space the wood heats and pick your climate, how much of your heat is wood, what kind of wood you burn and what you burn it in. You get the cords for the winter and how long the stack runs.
The appliance matters as much as the wood. A modern stove or insert gets about 70 percent of a cord's heat into the room; an open fireplace gets about 10 percent. The same winter can take 3 cords or 18.
Start with the heat your house needs for a winter. The government's survey of home energy use puts space heating at about 54 million BTU a year for the average home in cold climates, 33 million in mixed climates and 15 million in mild, dry ones. Divided by those homes' heated area, that's about 29,900 BTU per square foot of heated space in a cold climate, 19,300 in a moderate one and 11,500 in a mild one.
Take the share the wood carries. If wood is your main heat, all of it; if the furnace does about half, half; for evening and weekend fires, about a quarter.
Divide by what a cord delivers. A cord of seasoned oak holds about 25.3 million BTU, mixed hardwood about 21.4 million, and pine or fir about 17.2 million. An EPA-certified stove or insert turns about 70 percent of that into heat in the room, an older stove about 47 percent, and an open fireplace about 10 percent.
Round up to the half cord, then convert. A full cord is a stack 4 feet high, 4 feet deep and 8 feet long. A face cord is the same height and length but only one 16-inch log deep, so three face cords make a full cord.
Worked example. 1,500 square feet in a cold climate, wood as the main heat, oak in a newer stove: 1,500 × 29,900 = 44.9 million BTU; one cord delivers 25.3 × 0.70 = 17.7 million; 44.9 ÷ 17.7 = 2.5, so about 3 cords, which is 9 face cords, or a stack 4 feet high, 4 feet deep and 24 feet long.
📐How it's calculated▼
Cords = square feet × winter heat per square foot × share from wood ÷ (heat per cord × stove efficiency), rounded up to the half cord.
Winter heat per square foot: cold 29,900 BTU, moderate 19,300, mild 11,500. Share: main heat 100%, about half 50%, evenings and weekends 25%.
Heat per cord: oak, hickory or sugar maple 25.3 million BTU; mixed hardwood 21.4; pine, fir or poplar 17.2. Efficiency: newer stove or insert 70%, older stove 47%, open fireplace 10%.
Face cords (16-inch logs) = cords × 3. Stack length at 4 feet high and 4 feet deep = cords × 8 feet.
Default: 1,500 × 29,900 ÷ (25.3 million × 0.70) = 2.5 → 3 cords, 9 face cords, a stack 24 feet long. The average cold-climate home, 1,808 square feet: 3.1 → 3.5 cords. Same house, older stove: 3.8 → 4 cords.
📎Sources:U.S. Energy Information Administration — 2020 Residential Energy Consumption Survey, space heating by climate (Table CE3.1),University of Maryland Extension — Heating with Wood (heat per cord by species, stove efficiency),Utah State University Extension — Wood Heating (cord and face cord definitions, heat per cord),U.S. EPA Burn Wise — Energy Efficiency and Your Wood-Burning Appliance
🔍Finding your inputs▼
Square feet the wood heats: The space the stove or fireplace actually keeps warm. If it heats the whole house, the whole house; if it keeps the main floor warm while the bedrooms rely on the furnace, just the main floor.
Your winters: Cold for the Northeast, Upper Midwest and mountains; moderate for the Mid-Atlantic, lower Midwest and Northwest; mild for the South, Southwest and coastal California.
How much of your heat is wood: Main heat if the stove runs all winter and the furnace barely comes on; about half if they share the load; evenings and weekends if the fire is mostly for comfort.
What you burn: Dense hardwoods like oak, hickory and sugar maple pack the most heat into a cord. Mixed hardwood is what many sellers deliver. Softwoods light fast and burn fast, so it takes more of them.
What you burn it in: A newer stove or insert with an EPA certification label, an older stove without one, or an open fireplace with no insert or glass doors.
⚠️Special situations▼
How many cords of wood to heat a 2,000 sq ft house?
In a cold climate with wood as the main heat, oak-class hardwood and a newer stove, about 3.5 cords a winter: 2,000 × 29,900 = 59.8 million BTU, and each cord delivers about 17.7 million. With an older stove it's about 5.5 cords, and with softwood in a newer stove about 5. In a moderate climate the same house takes about 2.5 cords.
How much is a face cord compared with a full cord?
A full cord is 4 feet high, 8 feet long and 4 feet deep, 128 cubic feet. A face cord is 4 feet high and 8 feet long but only as deep as the logs are long, so with 16-inch logs it's a third of a cord. Some sellers cut 12- or 18-inch logs, which makes their face cord a quarter or three-eighths of a cord, so compare prices per full cord.
We only have fires on weekends. How much wood do we need?
Pick "Evenings and weekends", which counts about a quarter of your heat, and enter the room the fireplace or stove warms rather than the whole house. For a 400-square-foot living room in a moderate climate with a newer stove, that's about half a cord a winter. In an open fireplace the same fires take about seven times the wood, though you're burning it for the fire, not the heat.
My wood is green. Does that change it?
Yes, and by more than people expect. The heat figures here assume wood dried to 20 percent moisture; freshly cut wood can be half water, and the fire spends its heat boiling that off before it warms the room. Split it into pieces about 6 inches across, stack it off the ground with the top covered so air moves through it, and check it with a moisture meter from the hardware store before you burn it.
❓Common questions▼
How many cords of wood do I need for winter?
For a house heated mainly by a newer wood stove in a cold climate, about 2.5 to 3.5 cords of seasoned hardwood for 1,200 to 2,000 square feet. The average cold-climate home, about 1,800 heated square feet, comes to about 3.5 cords. Softwood, an older stove, a drafty house or damp wood all push it up; a moderate climate or sharing the load with a furnace brings it down.
How big is a cord of wood?
A full cord is a neatly stacked pile 4 feet high, 8 feet long and 4 feet deep, 128 cubic feet of wood and air space. A face cord, sometimes called a rick or a short cord, is 4 feet high and 8 feet long but only one log deep, which for 16-inch logs is a third of a full cord.
Which firewood gives the most heat?
The densest hardwoods. A cord of seasoned hickory holds about 29 million BTU, oak about 25 to 27 million and sugar maple about 25 million, while pine is about 19 million and cottonwood about 16 million. So a winter that takes 3 cords of oak takes about 4 of pine.
Does a fireplace insert really save wood?
Yes, a lot. An open fireplace sends about nine-tenths of its heat up the chimney, while a certified insert or stove gets about 70 percent into the room, about seven times as much heat from the same cord. The EPA puts a certified stove at about a third less wood than an older uncertified one.
How do I know if firewood is seasoned?
Seasoned wood has dried to about 20 percent moisture or less. It's lighter, the ends are darker and cracked, and two pieces knocked together sound hollow rather than dull. A moisture meter is the sure test. Wetter wood gives noticeably less heat and more smoke and creosote.
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