Firewood Calculator
Cords of firewood in a stack — check you got what you paid for.
Input sheet
DIY at your own risk. Calcora's calculators and guides are general estimates and information only — not professional, engineering, legal, or safety advice. Always verify local building codes and permit requirements, and hire a licensed pro for electrical, gas, plumbing, structural, or any work you're not fully comfortable doing yourself.
Firewood's only honest unit is the cord — a legally defined 128 cubic feet of tightly stacked wood — and most short deliveries hide behind vaguer terms. This calculator measures a stack and tells you what fraction of a cord you actually have.
How it works
A full cord is a tightly stacked 4 × 4 × 8 ft pile — 128 cubic feet. Stack volume ÷ 128 gives cords; a face cord of 16 in logs is a third of that.
A full cord is any stack whose length × height × depth multiplies to 128 cubic feet; the classic arrangement is 4 ft high, 4 ft deep, 8 ft long. Measure the stack as it sits, multiply the three dimensions, and divide by 128.
The 'face cord' metric handles the common sale unit: a single row 4 ft high and 8 ft long, but only one log deep. With standard 16 in logs that is a third of a full cord — which matters, because face cords are often priced like they were more.
Cords = stack length × height × depth (ft) ÷ 128. A face cord of 16 in logs = ⅓ full cord.
Worked examples
The classic 8 ft long, 4 ft high, 4 ft deep stack. → Exactly 1.00 cord.
8 × 4 × 4 = 128 cu ft ÷ 128 = 1 cord.
A 12 ft long, 4 ft high row of 16 in logs. → About 0.50 cord — 1.5 face cords.
12 × 4 × 1.33 = 63.8 cu ft ÷ 128 ≈ 0.50 cord.
Tips & gotchas
- Measure the stack before the delivery truck leaves — a 'cord' dumped loose in the driveway can't be verified until stacked.
- Buy seasoned wood (under 20% moisture, checked ends, bark loosening) or buy green a year ahead and season it yourself.
- Stack off the ground on rails with the top covered and sides open — wrapped-tight tarps trap moisture and rot the pile.
FAQ
How much wood for a winter?
A home heating primarily with wood burns 3–5 cords a season; occasional fireplace use is well under one.
How long does wood take to season?
Six months to a year split and stacked for softwoods and most hardwoods; dense oak wants a full one to two years.
How much heat is in a cord?
Around 20–30 million BTU depending on species — dense hardwoods like oak and hickory sit at the top, pine near the bottom.
Related calculators
Concrete Calculator · Paint Calculator · Flooring Calculator · Mulch Calculator · Gravel & Driveway Calculator