Cord Firewood Calculator
Measure your wood stack and accurately calculate the number of full cords, total volume, estimated weight, and heating potential (BTUs).
1.00 Cords
128.00
3,800 lbs
26.4 M
3.00
Visual Volume Comparison
Comparison of your stack vs. 1 Standard Cord (128 ft³)
Note: A standard cord measures exactly 4′ x 4′ x 8′ when tightly stacked.
What is a cord firewood calculator?
A cord firewood calculator is a specialized tool designed to measure the volume of a wood stack and convert those measurements into standard units of firewood measurement, primarily the “cord.” Whether you are a homeowner preparing for winter or a wood seller verifying your inventory, understanding the exact volume of your wood is essential for fair pricing and heating planning.
A “cord” is the official unit of measurement for firewood in the United States and Canada. Many people use a cord firewood calculator to avoid the common pitfall of buying wood that is loosely stacked or shorter than advertised. By inputting the length, height, and width of your stack, you can determine if you have received a full cord, which must total 128 cubic feet of tightly stacked wood.
Common misconceptions include the idea that a “face cord” is the same as a “full cord.” A face cord is only a fraction of a full cord, usually one-third, depending on the length of the logs. Our calculator clarifies these discrepancies by providing both full cord and face cord equivalents.
Cord Firewood Calculator Formula and Mathematical Explanation
The mathematics behind the cord firewood calculator is based on volume geometry. The basic formula is:
To ensure accuracy, we convert all inch measurements into decimal feet before multiplication. For instance, 6 inches becomes 0.5 feet.
Variables and Units
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Length (L) | The horizontal span of the stack | Feet / Inches | 4ft – 24ft |
| Height (H) | The vertical measurement from ground to top | Feet / Inches | 2ft – 6ft |
| Width (W) | The depth of the stack (log length) | Feet / Inches | 12″ – 24″ (Standard 16″) |
| Species Factor | Density and BTU value per cord | lbs / BTU | 15M – 30M BTU |
Practical Examples (Real-World Use Cases)
A homeowner has a wood shed that is 12 feet long and 4 feet high. They stack their 16-inch (1.33 ft) logs to the top.
Inputs: L=12ft, H=4ft, W=1.33ft.
Calculation: (12 * 4 * 1.33) / 128 = 63.84 / 128 = 0.5 Cords.
Interpretation: This homeowner has exactly half a cord of wood.
A seller delivers a pile that is stacked 8 feet long, 4 feet high, and 4 feet deep.
Inputs: L=8ft, H=4ft, W=4ft.
Calculation: (8 * 4 * 4) / 128 = 128 / 128 = 1.0 Cord.
Interpretation: This is the legal definition of a full cord.
How to Use This Cord Firewood Calculator
- Measure your stack: Use a tape measure to find the length, height, and depth (width) of your wood pile.
- Input the dimensions: Enter the feet and remaining inches into the respective fields in the cord firewood calculator.
- Select your wood type: Choose the species (e.g., White Oak or Pine) to get accurate weight and energy estimates.
- Analyze the results: Look at the “Total Volume” in Cords. Our tool also shows the cubic feet, total weight (useful for trailer limits), and BTU output.
- Copy for records: Click “Copy Results” to save the data for your purchase receipt or heating logs.
Key Factors That Affect Cord Firewood Calculator Results
- Stacking Density: If wood is stacked loosely with large air gaps, the cord firewood calculator will overestimate the actual wood volume. Professional cords are “well-stacked.”
- Moisture Content: Green wood (unseasoned) weighs significantly more than dry wood. Use a firewood moisture tester to ensure your wood is below 20% for optimal burning.
- Wood Species: Hardwoods like Oak produce nearly double the heat of softwoods like Pine per cord. This affects your wood stove efficiency.
- Bark Thickness: Some species like Hickory have thick bark that contributes to volume but offers different BTU characteristics than the heartwood.
- Log Shape: Crooked or knotty logs don’t stack as tightly as straight, split logs, which can lead to a “short cord” even if the dimensions seem correct.
- Drying Shrinkage: Wood shrinks as it seasons. A green cord stacked at 128 cubic feet may shrink by 5-8% as it dries, which is why some professionals stack slightly over 4 feet high.
Frequently Asked Questions (FAQ)
What is the difference between a cord and a face cord?
A full cord is 128 cubic feet (usually 4’x4’x8′). A face cord is a single stack that is 4′ high and 8′ long, but the width is only the length of the logs (often 16 inches). Therefore, a face cord is typically 1/3 of a full cord.
How much does a cord of firewood weigh?
Weight varies by species and moisture. A cord of dry Oak weighs about 3,500 lbs, while a cord of dry Pine weighs only about 2,200 lbs. Green wood can weigh up to 5,000 lbs per cord.
What are the dimensions of a cord of wood?
The standard dimensions for a cord are 4 feet high, 8 feet long, and 4 feet deep. However, any combination of dimensions that equals 128 cubic feet is technically a cord.
How many BTUs are in a cord of wood?
Hardwoods generally range from 20 to 28 million BTUs per cord. Softwoods range from 14 to 18 million BTUs per cord.
How do I know if I’m getting a full cord?
Always measure the stack after it has been delivered and stacked. Use our cord firewood calculator to verify the cubic footage equals 128.
Does the cord firewood calculator account for air space?
The calculation assumes a “standard” tight stack. It cannot account for excessive air gaps caused by poor stacking techniques.
Can I calculate volume for a circular stack?
Circular stacks (Holz Hausen) require a different formula (π × r² × height). This calculator is designed for rectangular stacks.
Why is firewood sold by the cord?
It is the legally recognized unit of measurement for wood fuel to ensure consumers aren’t cheated by ambiguous terms like “truckload” or “pile.”
Related Tools and Internal Resources
- Firewood Storage Best Practices: Learn how to season your wood faster and prevent rot.
- Tree Weight Estimation: Calculate the weight of standing or felled trees before processing.
- Lumber Board Feet Calculator: If you are milling your logs instead of burning them, use this tool for lumber volume.
- Chainsaw Fuel Mixture Calculator: Ensure your saw runs perfectly with the right oil-to-gas ratio.