Calculating potential Btu's of your Firewood

Spike VM

This calculator can be used to calculate the amount of Btu's that are generated when burning wood.

The calculator uses basic specific gravity of a species, your values for the starting Btu's/per pound of wood, moisture content of wood and the cubic foot volume you wish to calculate for.

A list with specific gravity values for North American trees can be found at the bottom of the page.

Specific Gravity #
Moisture Content %
Btu's btu/lb
Cubic Feet ft³

Results:

Dry Density lbs/ft³
Weight Of this Wood @ Selected % MC lbs
Net Btu's Btu
Btu's in Millions MBTU

The Calculation

  1. enter the basic specific gravity of the wood.
  2. enter the amount of Btu's you wish to calculate for. (for most species use 8084 Btu's)
  3. enter the moisture content of the wood (percentage)
  4. enter the volume you wish to calculate for (using 85 for a cord of wood seems like a plan)

Results

  1. Density of wood @ 0%MC
  2. The total weight of the wood based on volume and moisture content.
  3. The amount of Btu's based on volume and moisture content.
  4. The amount of Btu's in millions

Basic Specific Gravity (based on oven-dry weight and green volume)

For the calculations we use the basic specific gravity of the species. That is the specific gravity (SG) when wood is at it lightest, oven dried, very close to 0% moisture content. Based on this SG value the dry density of the wood is calculated.

Btu's

One pound of oven dried wood weighs one pound and it doesn't matter what the species of the wood is. One pound of oven dried Oak wood has the same weight as one pound of oven dried Cedar and it is generally accepted that one pound of oven dried wood, wood @ 0% MC, can produce 8600 Btu's for most species. Due to the higher lignin and higher resin content found in some species (such as Pine trees) the gross available heating value can be as much as 9000 Btu's per pound of dry wood.

The total energy contained in wood is not completely converted to available heating energy.

Wood is made up of about 50% carbon, 6% hydrogen, 44% oxygen, and 1% of trace amounts of several metal ions. Loss due to moisture created from the combustion of hydrogen will reduce the available heat energy by about 6%.

8600Btu's - 6% = 8084 Btu's per pound of dried wood @ 0% MC. If you are calculating the amount of Btu's for your species of wood, 8084 Btu's is a good starting point and if you know that your firewood contains a lot of resin then you could use 9000 - 6% = 8460 Btu's as a starting point.

Moisture Content (MC)

Burning water is a waste of energy and the part that generates the available heat energy (Btu's) is the wood, not water.

And as such, the amount of moisture your wood contains will further reduce the amount of Btu's.

If you take a sample of one pound of oven dried wood, wood @ 0% MC, it will contain 1 lb of wood 0 lb of water. Wood @ 60 % MC will contain 0.625 lbs of wood and 0.375 lb water.

To calculate the Btu's available per pound of wood @ 60% MC = 8084 * 0.625 = 5052.5 Btu's

If you take the time to let your firewood dry to 20 % MC, wood @ 20% MC contains 0.833lb wood and 0.167 lb water. Calculate the Btu's available per pound of wood @ 20% MC = 8084 *0.833 = 6734 Btu's

Volume

If you are calculating based on a solid piece of round wood use the cubic feet volume of that piece of wood.

When you buy a cord of firewood the cord should fit within an area of 8 feet long x 4 feet high x 4 feet wide or any combination of those measurements that add up to 128 cubic feet. 8' x 4' x 4 ' = 128 cubic feet. Due to stacking there will be a large % of airspace in this stack of wood, drastically reducing the actual solid volume of the wood. Most available Btu's charts mention that they are based on that one cord of wood contains 80 to 85 cubic feet. That may seem a bit low but if you are using this calculator for comparison of Btu's for various species it can be used as a good starting point for calculating the Btu's a cord of firewood can produce.

TypeCommon NameBinomialBasic Specific Gravity
Hardwood Maple, Bigleaf / British Columbia / Broadleaf / Oregon Acer macrophyllum 0.440
Hardwood Maple, Boxelder / Ash-Leaf / Manitoba / Three-Leave Acer negundo 0.416
Hardwood Maple, Black / Black Sugar / Hard / Rock Acer nigrum 0.520
Hardwood Maple, Striped / Goosefoot / Moosewood / Snake Bark Acer pensylvanicum 0.440
Hardwood Maple, Red / Scarlet / Soft / Water Acer rubrum 0.490
Hardwood Maple, Silver Acer saccharinum 0.440
Hardwood Maple, Sugar Acer saccharum 0.560
Hardwood Buckeye, Yellow / Sweet Aesculus octandra 0.330
Hardwood Ailanthus / Tree Of Heaven Ailanthus altissima 0.460
Hardwood Alder, White / Rhombie Leaf Alnus rhombifolia 0.370
Hardwood Alder, Red Alnus rubra 0.370
Hardwood Canadian Serviceberry Amelanchier canadensis 0.660
Hardwood Serviceberry Amelanchier spp. 0.660
Hardwood Pond Apple, Alligator Apple Annona glabra 0.500
Hardwood Madrone, Pacific Arbutus menziesii 0.570
Hardwood Birch, Yellow / Black Betula alleghaniensis 0.550
Hardwood Birch, Sweet Betula lenta 0.600
Hardwood Birch, Alaska Paper Betula neoalaskana 0.530
Hardwood Birch, River Betula nigra 0.490
Hardwood Birch, Paper Betula papyrifera 0.480
Hardwood Birch, Gray Betula populifolia 0.450
Hardwood Gumbo-Limbo / Copperwood / Chaca Bursera simaruba 0.320
Hardwood American Hornbeam / Musclewood Carpinus caroliniana 0.580
Hardwood Hickory, Water / Bitter Pecan Carya aquatica 0.610
Hardwood Hickory, Bitternut / Swamp Carya cordiformis 0.600
Hardwood Hickory, Pignut Carya glabra 0.660
Hardwood Hickory, Pecan Carya illinoensis 0.600
Hardwood Hickory, True, Shellbark Carya laciniosa 0.620
Hardwood Hickory, Nutmeg Carya myristiciformis 0.560
Hardwood Hickory, True, Shagbark Carya ovata 0.640
Hardwood Hickory, Mockernut / White / White-Heart Carya tomentosa 0.640
Hardwood Chestnut, American Castanea dentata 0.400
Hardwood Chinquapin / Golden / Giant / Western Castanopsis chrysophylla 0.420
Hardwood Catalpa, Northern / Hardy / Western / Cigar Tree / Catawba Tree Catalpa speciosa 0.380
Hardwood Sugarberry / Southern Hackberry Celtis laevigata 0.470
Hardwood Hackberry Celtis occidentalis 0.490
Hardwood Mountain Mahogany / Birch Leaf Mountain Mahogany Cercocarpus betuloides 0.800
Hardwood Chinkapin, Giant / Golden Chrysolepis chrysophylla 0.420
Hardwood Buttonwood / Button Mangrove Conocarpus erectus 0.690
Hardwood Dogwood, Flowering Cornus florida 0.640
Hardwood Dogwood, Pacific / Mountain Dogwood Cornus nuttallii 0.580
Hardwood Hawthorn, Late / Pear Crataegus calpodendron 0.620
Hardwood Persimmon, Common Diospyros virginiana 0.640
Hardwood Redberry Stopper Eugenia confusa 0.810
Hardwood Inkwood / Butterbough Exothea paniculata 0.730
Hardwood Beech / American / North American Fagus grandifolia 0.560
Hardwood Ash, Biltmore / White Fraxinus americana 0.550
Hardwood Ash, Oregon / Water Fraxinus latifolia 0.500
Hardwood Ash, Black Fraxinus nigra 0.450
Hardwood Ash, Green / Bastard Fraxinus pennsylvanica 0.530
Hardwood Ash, Pumpkin / Red Fraxinus profunda 0.480
Hardwood Ash, Blue / Virginia Fraxinus quadrangulata 0.530
Hardwood Honey Locust / Honey Shucks / Sweet Bean Gleditsia triacanthos 0.600
Hardwood Kentucky Coffeetree Gymnocladus dioicus 0.530
Hardwood Carolina Silverbell / Little Silverbell Halesia carolina 0.420
Hardwood American Witch-Hazel Hamamelis virginiana 0.560
Hardwood Ocean Spray / Creambush / Ironwood Holodiscus discolor 0.710
Hardwood Holly, American / White Holly Ilex opaca 0.500
Hardwood Butternut / White Walnut Juglans cinerea 0.360
Hardwood Texas Walnut / Little Walnut Juglans microcarpa 0.530
Hardwood Walnut, Black Juglans nigra 0.510
Hardwood Mountain Laurel / Calico-Bush / Spoonwood Kalmia latifolia 0.620
Hardwood Sweetgum, American / American Storax / Hazel Pine / Satin-Walnut / Alligatorwood Liquidambar styraciflua 0.460
Hardwood Poplar-Yellow / American Tulip / Canary Whitewood Liriodendron tulipifera 0.400
Hardwood Tanoak / Tanbark-Oak Lithocarpus densiflorus 0.580
Hardwood Osage Orange / Horse Apple / Hedge Apple Maclura pomifera 0.760
Hardwood Magnolia, Cucumbertree / Blue Magnolia, Magnolia acuminata 0.440
Hardwood Magnolia, Fraser / Mountain Magnolia Magnolia fraseri 0.400
Hardwood Magnolia, Southern Magnolia grandiflora 0.460
Hardwood Magnolia, Sweetbay Magnolia virginiana 0.420
Hardwood Paradise Apple / Common Apple Malus pumila 0.646
Hardwood Apple / Common / Wild Malus sylvestris 0.610
Hardwood Tupelo, Water / Cottongum / Wild Olive / Large Tupelo Nyssa aquatica 0.460
Hardwood Sour Gum / Tupelo, Black Nyssa sylvatica 0.460
Hardwood Hophornbeam, American / Eastern Ostrya virginiana 0.630
Hardwood Sourwood / Sorrel Tree Oxydendrum arboreum 0.500
Hardwood Sycamore, American / American Planetree Platanus occidentalis 0.460
Hardwood Poplar, Abele / Silver Poplar / Silverleaf Poplar Populus alba 0.360
Hardwood Poplar, Balsam / Black / Hackmatack Populus balsamifera 0.310
Hardwood Cottonwood, Eastern / Eastern / Plains / MatchPoplar Populus deltoides 0.370
Hardwood Cottonwood, Fremont / Alamo Populus fremontii 0.410
Hardwood Aspen, Bigtooth / Large-tooth Populus grandidentata 0.360
Hardwood Aspen, Quaking / Trembling / Aspen Popular Populus tremuloides 0.350
Hardwood Cottonwood, Black Populus trichocarpa 0.310
Hardwood Mesquite Spp. Prosopis spp. 0.780
Hardwood Hollyleaf Cherry / Evergreen Cherry Prunus ilicifolia 0.730
Hardwood Bird Cherry / Fire Cherry / Pin Cherry Prunus pensylvanica 0.360
Hardwood Cherry, Black Prunus serotina 0.470
Hardwood Oak, White Quercus alba 0.600
Hardwood Oak, Arizona White / Arizona Quercus Arizonica 0.590
Hardwood Oak, Bastard White Quercus austrina 0.750
Hardwood Oak, Swamp White Quercus bicolor 0.640
Hardwood Oak, Chapman Quercus chapmanii 0.780
Hardwood Oak, Canyon Live / Canyon Oak / Maul Oak Quercus chrysolepis 0.700
Hardwood Oak, Scarlet Quercus coccinea 0.600
Hardwood Oak, Southern Red Quercus falcata 0.520
Hardwood Oak, Gambel / Rocky Mountain White / Colorado Scrub Quercus gambelii 0.620
Hardwood Oak, Garry / Oregon White Oak / Oregon Oak Quercus garryana 0.640
Hardwood Oak, Sand Live Quercus geminata 0.872
Hardwood Oak, Darlington / Laurel-Leaf Oak Quercus hemisphaerica 0.690
Hardwood Oak, Bluejack / Upland Willow Oak / Sandjack Oak / Cinnamon Oak Quercus incana 0.710
Hardwood Oak, California Black / Kellogg Oak Quercus kelloggii 0.510
Hardwood Oak, Turkey / Catesby / American Turkey Quercus laevis 0.639
Hardwood Oak, Laurel / Diamond-Leaf Oak / Water Oak Quercus laurifolia 0.560
Hardwood Oak, Overcup Quercus lyrata 0.570
Hardwood Oak, Bur / Mossy-Cup Quercus macrocarpa 0.580
Hardwood Oak, Sand Post Quercus margaretta 0.760
Hardwood Oak, Swamp Chestnut / Basket Quercus michauxii 0.600
Hardwood Oak, Dwarf Live / Minimal Quercus minima 0.890
Hardwood Oak, Myrtle / Shrubby Quercus myrtifolia 0.807
Hardwood Oak, Water Quercus nigra 0.560
Hardwood Oak, Cherrybark Quercus pagoda 0.610
Hardwood Oak, Pin / Swamp Spanish Quercus palustris 0.580
Hardwood Oak, Willow Quercus phellos 0.560
Hardwood Oak, Chestnut / Rock / Rock Chestnut / Mountain Quercus prinus 0.570
Hardwood Oak, Running / Runner Quercus pumila 0.710
Hardwood Oak, Northern Red Quercus rubra 0.560
Hardwood Oak, Shumard / Swamp Red / Shumard Red Quercus shumardii 0.640
Hardwood Oak, Post / Iron Quercus stellata 0.600
Hardwood Oak, Black / Eastern Black Quercus velutina 0.560
Hardwood Oak, Live / Southern Live Quercus virginiana 0.800
Hardwood Buckthorn, California Coffeeberry Rhamnus californica 0.500
Hardwood Buckthorn, Spiny Redberry Rhamnus crocea 0.750
Hardwood Buckthorn, Cascara Rhamnus purshiana 0.500
Hardwood Great Laurel / Rosebay Rhododendron Rhododendron maximum 0.500
Hardwood Locust, Black / False Acacia / Green / Locust / Shipmast / White / Yellow Robinia pseudoacacia 0.660
Hardwood Willow, Pacific Salix lasiandra 0.390
Hardwood Willow, Black / Black American Salix nigra 0.360
Hardwood Blue Elderberry / Blue Elder Sambucus caerulea 0.460
Hardwood Sassafras Sassafras albidum 0.420
Hardwood False Mastic / Yellow Mastic Sideroxylon foetidissimum 0.520
Hardwood Bully Trees Sideroxylon indet 1.234
Hardwood White Bully / Willow Bustic / Bustic Cassada Sideroxylon salicifolium 0.860
Hardwood Basswood, American / American Linden Tilia americana 0.320
Hardwood Basswood, White Tilia heterophylla 0.320
Hardwood Elm, Winged / Wahoo Ulmus alata 0.600
Hardwood Elm, American / White / Water / Florida Ulmus americana 0.460
Hardwood Elm, Texas Cedar / Cedar Elm Ulmus crassifolia 0.590
Hardwood Elm, Slippery / Red / Gray / Soft Ulmus rubra 0.480
Hardwood Elm, Rock, Elm Cork Ulmus thomasii 0.570
Hardwood Laurel, California / Oregon Myrtle Umbellularia californica 0.510
Soft Wood Fir, Pacific Silver / White / Red/ Lovely / Amabilis / Cascades Abies amabilis 0.400
Soft Wood Fir, Corkbark Abies arizonica 0.360
Soft Wood Fir, Balsam / Canadian / Canada / Balm of Gilead / Eastern Abies balsamea 0.330
Soft Wood Fir, White / Colorado / California White / Low's Abies concolor 0.370
Soft Wood Fir, Grand / Lowland / Lowland White / White / Silver Abies grandis 0.350
Soft Wood Fir, Subalpine / Alpine / Mountain Balsam / Rocky Mountain / White Balsam Abies lasiocarpa 0.310
Soft Wood Fir, Red / Golden / California Red / Shasta / Silvertip Abies magnifica 0.360
Soft Wood Fir, Noble Abies procera 0.370
Soft Wood Cedar, Incense Calocedrus decurrens 0.350
Soft Wood Cedar, Port-Orford Chamaecyparis lawsoniana 0.390
Soft Wood Cedar, Yellow / Alaska Chamaecyparis nootkatensis 0.420
Soft Wood Cedar, Atlantic White Chamaecyparis thyoides 0.310
Soft Wood Florida Strangler Fig / Golden Fig/ Higuerón Ficus aurea 0.440
Soft Wood Juniper, Alligator / Checkerbark Juniperus deppeana 0.480
Soft Wood Juniper, Western Juniperus occidentalis 0.450
Soft Wood Southern Redcedar Juniperus silicicola 0.420
Soft Wood Cedar, Eastern Redcedar Juniperus virginiana 0.440
Soft Wood Tamarack / Hackmatack / American Larch Alaskan / Eastern Larix laricina 0.490
Soft Wood Larch, Western / Montana / Mountain Larix occidentalis 0.480
Soft Wood Incense Cedar / California Incense-Cedar Libocedrus decurrens 0.350
Soft Wood Spruce, Engelmann / White Spruce / Mountain Spruce / Silver Spruce Picea engelmannii 0.330
Soft Wood Spruce, White / Alberta / Black Hills / Canada / Western White Picea glauca 0.330
Soft Wood Spruce, Black / Bog / shortleaf black / Swamp Picea mariana 0.380
Soft Wood Spruce, Red / Eastern / West Virginia Picea rubens 0.370
Soft Wood Spruce, Sitka / Coast / Menzies / Western Picea sitchensis 0.370
Soft Wood Pine, Knobcone / Narrowcone Pinus attenuata 0.390
Soft Wood Pine, Jack / Banksian / Black / Scrub Pinus banksiana 0.400
Soft Wood Pine, Sand Pinus clausa 0.460
Soft Wood Pine, Lodgepole / Bolander Beach / Shore / Tamarack Pine Pinus contorta 0.380
Soft Wood Pine, Coulter / Big-Cone Pine Pinus coulteri 0.400
Soft Wood Pine, Shortleaf / Arkansas / Shortstraw / Southern / Yellow Pinus echinata 0.470
Soft Wood Pine, Common / Two Needle Pinyon Pinus edulis 0.500
Soft Wood Pine, Slash / American Pitch / Caribbean / Salish / Longleaf Pitch / Swamp Pinus elliottii 0.540
Soft Wood Pine, Limber / Rocky Mountain White Pinus flexilis 0.370
Soft Wood Pine, Spruce / Bottom White / Cedar/ Poor / Walter Pinus glabra 0.410
Soft Wood Pine, Jeffrey / Black Pinus jeffreyi 0.370
Soft Wood Pine, Sugar / California Sugar Pinus lambertiana 0.340
Soft Wood Pine, Western White / Idaho White / Mountain White / Silver Pinus monticola 0.350
Soft Wood Pine, Bishop / Obispo / Swamp / Prickle-Cone Pinus muricata 0.450
Soft Wood Pine, Longleaf / Florida / Georgia Pinus palustris 0.540
Soft Wood Pine, Ponderosa / Western Yellow / Blackjack / Bull / Pacific Ponderosa / Rock Pinus ponderosa 0.380
Soft Wood Pine, Table Mountain / Hickory / Prickley Pinus pungens 0.490
Soft Wood Pine, Monterey / Cedros Island / Guadalupe Island / Radiata / Insignis Pinus radiata 0.400
Soft Wood Pine, Red / American Red / Canadian Red / Norway Pinus resinosa 0.410
Soft Wood Pine, Pitch / Hard Pinus rigida 0.470
Soft Wood Pine, Gray / California Foothill / Bull / Grey-leaf / Digger Pinus sabiniana 0.400
Soft Wood Pine, Pond / Bay / Marsh / Pocosin Pinus serotina 0.510
Soft Wood Pine, Eastern White / Northern White / Weymouth / White Pinus strobus 0.340
Soft Wood Pine, Loblolly / Frankincense / Oldfield / Southern Pinus taeda 0.470
Soft Wood Pine, Virginia / Jersey / Poverty / Scrub Pinus virginiana 0.450
Soft Wood Douglas-Fir, Coast Pseudotsuga menziesii 0.453
Soft Wood Douglas-Fir, Interior North Pseudotsuga menziesii 0.450
Soft Wood Douglas-Fir, Interior West Pseudotsuga menziesii 0.460
Soft Wood Redwood / California / Coast Sequoia sempervirens 0.380
Soft Wood Redwood, Giant / California Big-Tree / Giant Sequoia / Sequoia / Sierra Sequoiadendron giganteum 0.340
Soft Wood Bald Cypress / Swamp / Gulf / Red / Southern / White / Yellow Taxodium distichum 0.420
Soft Wood Yew, Pacific / Western / Canadian / Californian Taxus brevifolia 0.600
Soft Wood Cedar, Northern White / Arborvitae / Eastern Arborvitae / Swamp Thuja occidentalis 0.290
Soft Wood Cedar, Westernred / Pacific Red / Giant Arborvitae / Canoe / Giant/ Shinglewood Thuja plicata 0.310
Soft Wood Hemlock, Eastern / Canada / Hemlock Spruce Tsuga canadensis 0.380
Soft Wood Hemlock, Western / Pacific / West Coast Tsuga heterophylla 0.420
Soft Wood Hemlock, Mountain Tsuga mertensiana 0.420
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