Calculator
Example data table
| Scenario | Inputs | Stacked volume | Cords | Solid volume (approx) |
|---|---|---|---|---|
| Standard cord stack | 8 ft × 4 ft × 4 ft, packing 0.65 | 128.00 ft³ (3.6246 m³) | 1.000 | 83.20 ft³ (2.3560 m³) |
| Half-cord stack | 8 ft × 4 ft × 2 ft, packing 0.65 | 64.00 ft³ (1.8123 m³) | 0.500 | 41.60 ft³ (1.1780 m³) |
| 30 logs | 30 pcs, Ø 8 in, 16 in, packing 0.65 | ≈23.29 ft³ (0.6596 m³) | ≈0.182 | ≈15.14 ft³ (0.4287 m³) |
Example results are approximate and depend on diameter averages and stacking tightness.
Formula used
- Rectangular stack (stacked volume): Vstacked = L × W × H after converting inputs to meters.
- Logs by count (solid volume): Vsolid = n × π × (d/2)² × ℓ where d and ℓ are in meters.
- Packing factor: packing = Vsolid ÷ Vstacked. If you calculate logs, the calculator estimates stacked volume as Vstacked = Vsolid ÷ packing.
- Conversions: 1 m³ = 35.3147 ft³, 1 cord = 128 ft³ (stacked).
- Weight estimate (optional): Weight ≈ Vsolid × density(MC), with density(MC) ≈ density(20%) × (100 + MC) / 120.
How to use this calculator
- Pick Rectangular stack or Logs by count.
- Select the unit you will measure with.
- Enter your dimensions, then set a realistic packing factor.
- Optional: choose species and moisture for a weight estimate.
- Press Calculate to see results above the form.
- Use Download CSV or Download PDF for records.
Planning storage and seasonal supply
Garden heating projects, outdoor ovens, and smokehouses depend on predictable fuel. By entering your stack dimensions or individual log count, the calculator returns stacked volume, solid wood volume, and common buying units. This helps you size a dry, raised rack, leave airflow clearance, and avoid ground contact that attracts rot and pests.
Use the unit selector to match your tape, then record results after each delivery. Many gardens target 0.25–1.0 cords for weekend fire pits, while larger cooking areas may need more during colder peak months.
Stacked volume versus solid wood
Stacked volume is the outer box of the pile, including air gaps. Solid volume estimates the actual wood content using a packing factor. Tight, uniform splits can reach about 0.70, while round, crooked, or loosely thrown pieces may fall near 0.55. Tracking both values improves comparisons between suppliers and stacking styles.
Packing factor selection with quick checks
Start with 0.65 for typical split firewood. If your pile has many rounds, bark slabs, or mixed lengths, reduce the factor. If the pieces are consistent, well-stacked, and aligned, increase it slightly. Re-check occasionally by measuring the same rack after settling; a small drop in height often indicates increased packing.
Conversions used for purchasing decisions
The tool converts between cubic meters and cubic feet, then reports cords and face cords. A full cord equals 128 cubic feet of stacked wood. A face cord is commonly a 4×8 stack one log-length deep; the calculator uses a 16-inch depth reference so you can scale results for other depths when markets vary.
Weight estimates for handling and transport
When enabled, weight is computed from solid volume and an air-dry density adjusted by moisture content. This is useful for trailer loading, wheelbarrow planning, and checking whether a raised bed edge, patio, or storage shelf can handle the load. Use the estimate as guidance, because species mix and moisture vary.
FAQs
What is a packing factor?
It is the ratio of solid wood volume to stacked volume. Because piles contain air gaps, solid wood is usually about 0.55–0.70 of the stacked box, depending on split uniformity and stacking tightness.
What is the difference between a cord and a face cord?
A cord is 128 cubic feet of stacked wood (typically 4×4×8 ft). A face cord is usually a 4×8 ft stack one log-length deep. Depth varies by market, so compare carefully.
How should I measure a stack?
Measure the outside length, width, and average height of the pile or rack. Use the same unit throughout. For uneven tops, take several height readings and average them for a more stable estimate.
How accurate is the logs-by-count method?
It assumes each piece is a cylinder using your average diameter and length. Mixed diameters reduce accuracy. Improve results by grouping logs into two or three diameter bands, calculating each band separately, and adding totals.
Can I use metric units for cords?
Yes. Enter measurements in meters, centimeters, or millimeters, and the calculator converts to cubic meters, cubic feet, cords, and face cords. This makes it easier to compare local suppliers with international reference volumes.
Why does the weight estimate change with moisture?
Water adds mass without adding much usable heat per unit weight. The calculator scales density using your moisture percentage, so wetter wood shows higher weight. Treat it as an estimate; species mix, bark, and drying vary.