Firewood Cord Calculator: Cords Per Winter, BTU by Species, and Season Cost

Properly seasoning firewood takes 6 to 24 months depending on the species, initial moisture content, how the wood is split, and the drying conditions. Hardwoods with high initial moisture content (freshly cut oak can be 50+ percent moisture by weight) take the longest: white oak, hickory, and beech should ideally season for 12 to 18 months before burning. Softer, more porous woods like ash, box elder, and some maples can season in 6 to 12 months. To season firewood correctly: split the wood to the final burn size (splitting dramatically increases the surface area for moisture evaporation); stack it in rows no more than 2 to 3 logs deep on a base that keeps wood off the ground; orient rows north-south where possible to expose both sides to prevailing winds; cover the top of the stack to keep rain off but leave the sides open for air circulation; and store in a location with good sun and wind exposure. Well-seasoned wood feels lighter than green wood of the same size, makes a hollow sound when pieces are knocked together, has visible checks (cracks) in the end grain, and has peeling or loose bark. Kiln-dried firewood reaches moisture content below 15 percent in a matter of days in a commercial kiln and is the most consistent fuel, though it typically costs significantly more per cord than air-dried wood from local suppliers.

The EPA and the wood heating industry recommend burning firewood with moisture content of 20 percent or less for best efficiency and lowest smoke emissions. At 20 percent moisture content, wood is considered “air dry” or “well seasoned” and delivers approximately 90 percent of its theoretical dry-basis BTU content. Below 15 percent (kiln-dried range), you get approximately 95 to 97 percent of dry BTU content with the cleanest burn. Above 25 to 30 percent moisture content, fire output drops noticeably, the fire is harder to start and maintain, and creosote production increases substantially. At 40 to 50 percent moisture content (green firewood), you are essentially trying to burn wet wood, and the result is a cool, smoky fire that coats the chimney with creosote at an accelerated rate. A wood moisture meter, available at hardware stores for $20 to $50, takes the guesswork out of moisture measurement. Insert the probes into a freshly split face of the wood for the most accurate reading; measuring the cut end or bark surface gives unreliable results. The EPA Burn Wise program provides guidance on proper wood moisture targets and burning practices.

The best firewood species for a wood stove are those with the highest BTU per cord in your geographic area. In the Eastern US: white oak (26.4 MMBtu/cord), red oak (24.6 MMBtu/cord), white ash (24.2 MMBtu/cord), sugar maple (25.5 MMBtu/cord), hickory (27.7 MMBtu/cord), and beech (26.5 MMBtu/cord) are all excellent choices that are widely available and well-regarded for their heat output, ease of splitting, and reliable seasoning. In the South and Southwest: live oak (30.0 MMBtu/cord) and mesquite (28.0 MMBtu/cord) are exceptional fuels where available. In the Pacific Northwest: Douglas fir (20.7 MMBtu/cord) is the workhorse fuel, commonly available and easy to work with, though lower in BTU than Eastern hardwoods. Avoid softwoods like pine and cedar for primary heating in any enclosed stove; their high resin content produces more creosote than hardwoods, increasing chimney cleaning frequency and fire risk. Pine kindling is widely used for starting fires but is not appropriate as the primary fuel. Aspen and cottonwood are sometimes available cheaply or free in parts of the Midwest and Mountain West, but their low BTU content (14 to 17 MMBtu/cord) means you need nearly twice as many cords as oak for the same heat output.

You can burn green firewood, but it is strongly discouraged for several practical and safety reasons. Green wood burns at lower temperatures than dry wood because a substantial portion of the combustion energy goes into evaporating the water in the wood before any heat reaches the room. The cooler, incomplete combustion of green wood produces much more smoke and a significantly higher rate of creosote deposition in the chimney. Creosote is the dark, tarry substance that builds up in chimneys from wood combustion; it is highly flammable and is the primary cause of chimney fires in the US. The National Fire Protection Association reports that failure to clean chimneys is the leading factor in chimney fires, and burning green wood dramatically accelerates creosote buildup. In terms of efficiency: green wood delivers only 55 to 65 percent of the BTU content of the same wood properly dried, making your wood supply go significantly further if you take the time to properly season it. If you must burn green wood in an emergency, use the smallest pieces possible, maintain a hot fire, and plan to have your chimney cleaned more frequently than with dry wood.

To measure a full cord: ask the seller to stack the wood (or stack it yourself after delivery). Measure the height, length, and width of the stack in feet. Multiply the three dimensions: a full cord = 128 cubic feet (4 x 4 x 8 = 128). For stacks with irregular dimensions, measure the actual height, length, and depth of the log pieces. A face cord of 16-inch logs stacked 4 feet high and 8 feet long = 4 x 8 x 1.333 = 42.7 cubic feet = exactly one-third of a full cord. Most states have laws requiring firewood sellers to advertise and sell by the cord (or fractions of a cord, like face cord) with clear disclosure of log length. If a seller quotes you “a load” or “a truckload” without specifying cord equivalent, ask for clarification in writing before purchase. Common sources of consumer complaints in the firewood market: sellers delivering a face cord when the buyer assumed a full cord; log lengths shorter than specified (affecting face cord value); wood that is poorly seasoned or mixed with low-quality species. For purchases from an unknown seller, request delivery and stacking in a single, measurable stack so you can verify the amount before the seller leaves.

Signs of properly seasoned firewood: the wood feels noticeably lighter than green wood of the same species and size; the bark is loose or peeling away from the wood; the end grain shows cracks (checking) radiating from the center outward; when two pieces are knocked together, they make a sharp, resonant crack rather than the dull thud of wet wood; the wood has a faded, grayish appearance rather than the bright, fresh-cut color of green wood. For a definitive measurement, use a pin-type moisture meter: insert the probes into a freshly split face of the wood and read the moisture percentage. At 20 percent or below, the wood is ready to burn efficiently. The most reliable method is to split a piece and test the interior, as the surface of stacked wood may appear dry while the center remains wet. Be aware that some vendors sell wood labeled “seasoned” that has only been cut and stored briefly; the only reliable check is measurement or buying from a reputable local supplier with a track record for well-dried wood.

Creosote is a collective term for the organic compounds deposited on chimney walls when wood smoke cools before leaving the flue. It ranges from light, sooty deposits (Stage 1, easily brushed away) to tar-like or hardened glassy deposits (Stage 3, very difficult to remove and highly combustible). Chimney fires start when creosote deposits ignite inside the flue; they can burn at over 2,000 degrees Fahrenheit, potentially cracking the flue liner and spreading fire to the structure. The three main causes of accelerated creosote buildup: burning green or wet wood (cooler, incomplete combustion); restricted air supply (smoldering, low-oxygen fires produce far more smoke condensation); and oversized flues or poorly fitted stoves that allow gases to cool too much before exiting. Prevention: burn only properly seasoned wood (20 percent or below moisture); burn hot fires, especially at startup and shutdown; have the chimney inspected and cleaned by a certified chimney sweep annually per NFPA 211 recommendations. Look for a chimney sweep certified by the Chimney Safety Institute of America (CSIA). The CSIA publishes guidelines for chimney maintenance and certified sweep directories.

In botanical terms, hardwoods are deciduous trees (lose their leaves annually) and softwoods are conifers (evergreens with needles). In firewood terms, hardwoods are generally denser and contain more BTUs per cord than softwoods. Common US hardwood firewood species: oak, maple, ash, hickory, birch, beech. Common softwood firewood species: pine, fir, cedar, spruce. The BTU-per-cord difference is significant: hickory at 27.7 MMBtu/cord versus eastern white pine at 15.9 MMBtu/cord. However, softwoods are not necessarily bad firewood; they split easily, ignite quickly, and work well for kindling or in situations where the low cost offsets the lower energy density (Douglas fir at 20.7 MMBtu/cord is a perfectly good primary fuel in the Pacific Northwest where it is readily available and competitively priced). The main practical concern with softwoods: their higher resin content tends to produce more creosote than hardwoods, especially when burned at low temperatures. Use softwoods for starting fires and early-evening burns when you can maintain a hot fire; use hardwoods for overnight loading when a stove is dampened and combustion is slower.

Proper firewood storage serves two purposes: continuing to dry green wood toward usable moisture content, and protecting seasoned wood from re-wetting. Basic storage guidelines: keep wood off the ground using pallets, poles, or commercial firewood racks to allow airflow underneath and prevent moisture wicking from the soil; stack wood in single-row stacks no more than two logs deep, with good airflow between pieces; cover the top of the stack (not the sides) with a tarp or metal roofing to shed rain and snow while allowing sides to breathe; locate the wood pile in a sunny, well-ventilated spot away from the house foundation (firewood stacked against a house can provide a pathway for insects and moisture into the structure). For winter access, keep a small indoor supply (one to three days of wood) near the stove and rotate from the outdoor stack. Never store large amounts of wood indoors; firewood harbors insects including carpenter ants, wood-boring beetles, and occasionally bark scorpions or black widow spiders in southern climates. Store outdoor wood at least 30 feet from the home’s foundation to reduce pest introduction risk, per guidance from most university extension pest management programs.

Enormously. The difference in firewood consumption between an old pre-1990 wood stove (65% efficient) and a 2020 EPA Step 2 stove (87% efficient) is 25 to 30 percent on cord count for the same heat output. For a home burning 4 cords per season in an old stove, upgrading to an EPA Step 2 stove reduces consumption to approximately 3.0 to 3.1 cords per season for the same delivered heat. At $300 per cord, that is a saving of $270 to $300 per year in firewood cost. Over the 20+ year life of a quality wood stove, the cumulative fuel savings can easily exceed the purchase price of the stove. EPA-certified wood stoves manufactured after 2015 must emit no more than 4.5 grams of particulate matter per hour (the 2015 standard). Step 2 stoves meeting the 2020 standard emit no more than 2.0 grams per hour, which is a 95 percent reduction in particulates compared to uncertified pre-1990 stoves. Many states offer tax credits or rebates for replacing older wood stoves with EPA Step 2 certified units; check with your state energy office or the EPA Burn Wise program for current incentive programs in your area.

Firewood prices vary dramatically by region, species, and condition. National ranges for 2024 to 2025: green or freshly cut hardwood cord: $100 to $200 in rural areas with local supply; seasoned hardwood delivered and stacked: $200 to $450 per cord in most rural and suburban markets; premium seasoned hardwood (hickory, white oak) in urban and suburban Northeast: $400 to $600 per cord delivered. Kiln-dried firewood, increasingly available at grocery stores, hardware chains, and firewood retailers: typically $6 to $10 per bundle of about 0.75 cubic feet, which works out to $800 to $1,600 per cord equivalent; extremely expensive compared to bulk cord purchases, appropriate only for occasional campfire use or emergency supply. Pacific Northwest: $200 to $300 per cord of Douglas fir or alder, split and delivered. Southeast and Gulf Coast: $150 to $280 per cord of mixed hardwoods. Great Plains and Midwest: $200 to $350 per cord of oak or hickory where available. The best prices typically come from buying direct from local woodlot owners or tree services, or from buying green wood in late spring and seasoning it yourself over the summer. Buying wood in the fall during peak demand typically costs 20 to 40 percent more than buying the previous spring for the same product.

Wood stove sizing is based on the peak heating demand of the space you want to heat, measured in BTU per hour. Rule of thumb: 20 to 30 BTU per hour per square foot for well-insulated modern homes; 30 to 50 BTU per hour per square foot for average homes; 50 to 70 BTU per hour per square foot for poorly insulated older homes. For a 1,000 square foot open-plan area in a well-insulated home in a cold climate: 1,000 x 30 = 30,000 BTU/hour peak demand. A mid-size wood stove with 40,000 to 60,000 BTU/hour maximum output would heat this space comfortably, running at partial load most of the time. Oversizing a wood stove is almost as problematic as undersizing: an oversized stove burns in a damped-down, smoldering mode most of the time, producing poor combustion efficiency and high creosote output. Correctly sized stoves run near their designed output range for clean, efficient combustion. Wood stove manufacturers publish heating area ratings (in square feet) for their products; use these as starting points, then adjust downward for poorly insulated homes or open floor plans with significant heat loss, and upward for very tight, well-insulated homes. The wood stove industry recommends consulting a certified hearth retailer for final sizing recommendations specific to your home’s layout and construction.

Burning firewood has complex environmental implications. On the carbon side: burning wood releases carbon dioxide that was recently captured from the atmosphere during the tree’s growth, making it roughly carbon-neutral over the lifecycle of sustainably managed forests, unlike burning fossil fuels that release carbon sequestered millions of years ago. Sustainably harvested firewood from local forests that are regenerating replaces dead wood that would eventually release its carbon through decomposition anyway. The EPA, USDA Forest Service, and many environmental organizations recognize sustainably harvested firewood as a low-carbon renewable fuel in the context of managed forests and proper burning practices. On the air quality side: wood combustion produces particulate matter (PM2.5) and volatile organic compounds, particularly from older stoves and from burning wet wood. Modern EPA Step 2 certified stoves reduce particulate emissions by up to 95 percent compared to pre-1990 stoves, making them far cleaner than their predecessors and cleaner than most residential oil burners on a per-BTU basis. Local air quality regulations in some US metro areas restrict wood burning on Spare the Air days or require EPA-certified appliances. Check your local air quality district for any burning restrictions in your area before installing a wood-burning appliance.

A “truckload” of firewood is an informal term with no standard definition, and this is a common source of confusion and occasionally of consumer disputes. What a truckload contains depends entirely on the size of the truck: a standard pickup truck with a full-size bed can hold approximately 0.4 to 0.7 cords of stacked wood. A 1-ton dump truck typically delivers 1 to 1.5 cords. A medium-size dump truck (3 to 5 cubic yard capacity) may hold 1.5 to 2 cords. A large tri-axle dump truck can carry 3 to 5 cords. When a firewood supplier quotes you a price “per truckload,” always ask for the equivalent in full cords and the log length, so you can make a valid comparison to other suppliers. In most US states, it is a deceptive trade practice to advertise firewood in units other than cords (or fractions or multiples of cords) without disclosure of the cubic footage. If you have a dispute with a firewood supplier about quantity delivered, most state department of agriculture or weights and measures offices can investigate complaints about firewood sales. Protect yourself by asking the seller to stack the wood on delivery and measuring it before they leave.

The National Fire Protection Association Standard 211 and the Chimney Safety Institute of America both recommend having chimneys, fireplaces, and vents inspected annually, with cleaning performed as needed based on inspection findings. For a primary wood stove burning 2 to 6 cords of properly seasoned wood per season in a properly sized stove, annual cleaning is typically appropriate and is the standard recommendation. If you burn green or wet wood, burn the stove in a heavily damped-down mode frequently, or have an older, less-efficient stove, more frequent cleaning (every half season or every 1 to 2 cords) may be warranted. NFPA 211 specifies that chimneys should be cleaned when deposits are 1/8 inch or more thick. Level 3 creosote (hardened, glazed deposits) requires professional removal with specialized tools and may indicate the need for liner repair or replacement. Signs that cleaning is overdue: visible soot or debris falling from the chimney into the firebox; a strong smoke or tar odor when the stove is not in use; dark, heavy smoking on startup that does not clear quickly; or any restriction of draft that makes the stove difficult to operate. Annual sweeping before the heating season begins is the most practical approach for most US homeowners; schedule the cleaning in summer or early fall while certified sweeps are less busy and before the heating season demand peaks.

Pellet stoves and wood stoves both burn wood-based fuel but differ substantially in how they operate and what they demand from the homeowner. Pellet stoves burn compressed wood pellets fed automatically from a hopper by an auger motor; most can run unattended for 24 to 48 hours and thermostat-controlled models regulate output automatically. They achieve 80 to 90 percent efficiency because combustion is precisely controlled and the exhaust is vented through small-diameter PVC or stainless-steel pipe rather than a full masonry chimney. Wood stoves require manual loading every 4 to 8 hours (depending on size and load), operate without electricity (a major advantage in outages), and vent through a conventional chimney. Pellet stoves require electricity to run the auger, combustion blower, and controls; they stop working in a power outage unless you have a battery backup. Cost per MMBtu comparison: pellet fuel at $250 per ton provides approximately 8,000 pounds of pellets (ton = 2,000 lbs) at approximately 8,000 BTU per pound and 75% stove efficiency = approximately 6 MMBtu per $250 = $41 per MMBtu. Quality firewood in a wood stove at $300 per cord and 80% efficiency delivers 19 to 22 MMBtu per cord at $14 to $16 per MMBtu. Well-sourced firewood heated in an efficient wood stove is typically less expensive per MMBtu than pellets, though pellets win on convenience and automatic operation. See the Pellet Stove Fuel Calculator for detailed pellet sizing and cost comparison.