Firewood Cord Calculator

A full cord of firewood is a stack 4 ft high, 4 ft deep and 8 ft long: 128 cubic feet of wood, bark and air. A face cord (also called a rick or stove cord) is a stack 4 ft high and 8 ft long at whatever length the pieces are cut, so its volume depends on the piece length. Measure your stack below to see what you have, then estimate how much wood a winter takes.

How the calculation works

Stack volume. Volume in cubic feet = length (ft) x height (ft) x depth (in) / 12. Measure the average height, and use the piece length as the depth for a single row.
Full cords. Full cords = volume / 128.
Face cords. Face cords = length x height / 32, since a face cord is a 4 by 8 ft face. How many face cords make a full cord depends on piece length: 48 / piece length in inches. With 16 in pieces, three face cords make one full cord.
Wood for a winter. Seasonal heat need = heated square feet x a seasonal heat figure for your climate zone x the share of your heat that comes from wood. Each cord delivers its heat content (million BTU per cord for the species, air-dried) x the efficiency of the stove or fireplace. Cords needed = seasonal heat need / usable heat per cord.

Worked example

A row 8 ft long and 4 ft high of 16 in pieces is 8 x 4 x 16 / 12 = 42.7 cu ft. That is 42.7 / 128 = 0.33 full cords, or exactly 1 face cord.

Now the winter estimate. A 1,500 sq ft home in climate zone 5 (Ohio, Pennsylvania, Iowa) uses a planning figure of 40,000 BTU per sq ft per season, so 1,500 x 40,000 = 60 million BTU if wood supplies all the heat. Oak averages about 24.9 million BTU per cord, and an EPA-certified stove at about 70% efficiency turns that into 17.4 million BTU of usable heat. 60 / 17.4 = about 3.4 full cords, or roughly 2.8 to 4.1 cords depending on the winter and how dry the wood is. Burn pine instead and the same house needs more than 5 cords.

Assumptions and limits

The seasonal heat figures by climate zone and the appliance efficiencies are planning values, not measurements of your home. Real use swings with the winter, how tight the house is, how warm you keep it and, above all, how dry the wood is: wet wood spends a large part of its heat boiling off water. Sellers’ “cords” also vary. Ask whether a price is for a full cord or a face cord, and measure what is delivered.

Storage safety

Stack firewood on stable, level ground, no higher than the rack is rated for, and keep large stacks away from the house to limit pests and fire risk. Store only a few days' worth indoors, away from the stove's clearance zone. Read our Safety Disclaimer.

Frequently Asked Questions

How big is a cord of firewood?

A full cord is 128 cubic feet: a stack 4 ft high, 4 ft deep and 8 ft long. That includes the air between pieces, so the solid wood in a cord is usually closer to 80 to 90 cubic feet, depending on how tightly it is stacked.

What is the difference between a face cord and a full cord?

A face cord is one row 4 ft high and 8 ft long at whatever length the pieces are cut. With common 16 in pieces, three face cords equal one full cord. With 12 in pieces it takes four. Always ask a seller for the piece length.

How many cords of wood do I need for a winter?

For a home heated mainly by an efficient wood stove, a common range is 3 to 6 full cords of hardwood in cold northern climates and 1 to 3 cords where winters are milder or wood is a supplement. Use the calculator above with your own square footage, climate zone and wood to get a planning number.

Does the type of wood change how much I need?

Yes. A cord of dense hardwood such as oak, hickory or black locust holds much more heat than a cord of pine, aspen or cottonwood, so you need fewer cords of hardwood for the same winter. Compare species in our firewood species table.

How much does a cord of wood weigh?

Seasoned hardwood typically weighs about 3,000 to 4,500 lb per full cord, and softwood about 2,000 to 3,000 lb. Green wood can weigh much more because of its water content, which is why a full cord rarely fits in a pickup bed in one trip.

Firewood storage and handling guides

Next: browse firewood storage and firewood handling guides, or check how dry your wood is with a moisture meter.