The calculator estimates your annual BTU heating requirement based on four inputs: climate zone (from your zip code), home square footage, insulation quality, and stove type. It then divides your total BTU need by each species’ BTU per cord to calculate how many cords you would burn per season.

Heating degree days (HDD) measure how cold your climate is over a full year. For each day that the average outdoor temperature is below 65 degrees Fahrenheit, the difference is added to the HDD total. Higher HDD means a colder climate and more firewood needed. For example, northern Minnesota has about 9,800 HDD while Tennessee has about 3,500.

The calculator provides a solid planning estimate based on widely accepted heat-loss formulas and NOAA climate data. Actual consumption varies based on factors like home layout, window quality, wind exposure, and how consistently you burn. Most users find the estimate within 15 to 20 percent of their real-world usage.