Understanding the Cord of Wood Calculator
A cord is the standard volume measurement for stacked firewood. It is defined as 128 cubic feet of wood, conventionally stacked in a rank 4 feet high, 4 feet deep, and 8 feet long. This tool takes the outer dimensions of your woodpile — length, height, and how deep the logs are cut — and converts that stack into full cords, the smaller "face cord" unit firewood is often sold in, and an estimated dollar cost.
The formula
The math is simple volume geometry:
- Stacked volume (cubic feet) = stack length (ft) × stack height (ft) × depth (ft), where depth is your log length converted from inches to feet.
- Full cords = stacked volume ÷ 128, since one cord is defined as exactly 128 cubic feet.
- Face cords (ricks) = full cords × (48 ÷ log length in inches). A face cord is a 4 ft × 8 ft stack whose depth is whatever length the logs were cut to, so a shallower stack takes more face cords to equal one full cord.
For example, a stack 8 ft long, 4 ft high, and 16 in deep has a volume of 8 × 4 × (16/12) = 42.67 cubic feet, which is 42.67 ÷ 128 ≈ 0.33 full cords — about one-third of a cord, or one 16-inch face cord.
Common reference points
- Full cord: 4 ft × 4 ft × 8 ft = 128 cubic feet.
- Face cord at 12 in depth: 4 ft × 8 ft × 1 ft = 32 cubic feet ≈ 1/4 cord.
- Face cord at 16 in depth: 4 ft × 8 ft × 1.33 ft ≈ 42.7 cubic feet ≈ 1/3 cord.
- Face cord at 24 in depth: 4 ft × 8 ft × 2 ft = 64 cubic feet = 1/2 cord.
What the formula does not measure
A cord measures the space a stack occupies, not the solid wood inside it. Round or loosely stacked logs leave more air gaps than tightly split, neatly stacked wood, so two "one-cord" piles can contain slightly different amounts of actual timber even though both measure 128 cubic feet. The formula also does not account for wood species, moisture content, or heat value (BTUs) — it is strictly a volume conversion.