There is a lot you should keep in mind when figuring out how long a cord of firewood will last you. A cord of wood should have dimensions four feet high by four feet wide by eight feet long, with a volume of 128 cubic feet. Considering this measurement, if you only plan on using the firewood for a fire pit on weekends, a cord should last you a season. If you plan on heating your home with firewood, you should look more at getting 5 or more cords of firewood for the winter season.