How Much Firewood is a free calculator for anyone who heats with wood. It answers one question well: how much wood do you need to get through the winter?
Most firewood guides give a rule of thumb. This calculator works from the physics instead: how much heat your home loses in your climate, how much of it you cover with wood, how efficient your stove is, and how much energy your wood holds at its moisture level. It also shows how a season of wood heat compares in cost with natural gas, heating oil, propane and a heat pump.
Where the numbers come from
Heat values per cord are typical published figures for seasoned wood at about 20% moisture. Climate presets use heating degree days for representative cities. Stove efficiencies follow typical ranges for open fireplaces, older stoves, inserts and modern EPA and Ecodesign stoves. Fuel prices are editable defaults; enter your own for the most accurate comparison.
The results are estimates for planning. Your actual use depends on how you run your stove and how cold the winter turns out, so we suggest stacking about 20% extra.