Standard American Wire Gauge sizes. Affects diameter and density per meter.
$ USD
€ EUR
£ GBP
Price per unit of weight selected above (e.g., $3.50 per kg).
Estimated Total Length
0.00 meters
0.00 feet
Total Estimated Value
$0.00
Wire Diameter
0.00 mm
Weight per Meter
0.00 g/m
*Calculation assumes solid bare copper density of 8.96 g/cm³. Stranded wire may vary slightly.
Specification Breakdown
Property
Metric Value
Imperial Value
Length vs. Weight Visualization
Visualizing the linear relationship for the selected gauge.
What is a Copper Wire Weight to Length Calculator?
A copper wire weight to length calculator is a specialized engineering and scrap metal tool designed to determine the linear footage or meterage of a coil of wire based solely on its mass and gauge (thickness). Whether you are an electrician estimating the remaining wire on a partial spool, a scrap dealer valuing a bundle of bare bright copper, or a hobbyist needing precise lengths for winding coils, knowing the relationship between weight and length is critical.
Many professionals rely on guesswork when dealing with partial spools. However, because copper has a consistent density (approximately 8.96 g/cm³), a copper wire weight to length calculator can provide highly accurate results. This tool eliminates the need to manually unspool and measure wire, saving time and preventing tangles.
Copper Wire Weight to Length Calculator Formula
The core logic behind a copper wire weight to length calculator is derived from the definition of density and the geometry of a cylinder. Since wire is essentially a very long cylinder, we use the following physics derivation:
Length (L) = Volume (V) / Cross-Sectional Area (A)
Where:
V = Mass (M) / Density (ρ)
A = π × (Diameter / 2)²
Combining these, the master formula used by this calculator is:
L = M / (ρ × π × r²)
Variable Definitions
Variable
Meaning
Unit (Metric)
Typical Range
M
Mass (Weight)
grams (g)
1g – 1000kg
ρ (Rho)
Density of Copper
g/cm³
8.96 (constant)
r
Radius (Diameter/2)
centimeters (cm)
0.005cm – 0.6cm
L
Resulting Length
centimeters (cm)
Varies
Practical Examples: Using the Copper Wire Weight to Length Calculator
Example 1: The Scrap Yard Estimate
A recycler receives a bundle of bare bright 12 AWG copper wire weighing exactly 5 kg. To verify if the length matches the inventory tag, they use the copper wire weight to length calculator.
Input Weight: 5 kg (5000 g)
Input Gauge: 12 AWG (Diameter ≈ 2.05 mm)
Calculation: The calculator determines the cross-sectional area and divides the total volume by this area.
Result: Approximately 169 meters (554 feet) of wire.
Financial Value: If copper is $8.00/kg, the total value is $40.00.
Example 2: The Electrician's Partial Spool
An electrician finds a partial spool of 6 AWG THHN wire. He weighs the wire (subtracting the spool weight) and finds he has 15 lbs of copper.
Input Weight: 15 lbs
Input Gauge: 6 AWG
Result: The calculator outputs roughly 194 feet.
Decision: Since the next job run requires 200 feet, he knows immediately he needs to buy a new spool, avoiding a costly shortage mid-job.
How to Use This Copper Wire Weight to Length Calculator
Weigh Your Wire: obtain the net weight of the copper. If the wire is on a spool, weigh an empty spool of the same type and subtract that weight from the total.
Determine the Gauge (AWG): Look at the wire jacket or measure the diameter with a caliper if the printing is illegible. Select this in the "Wire Gauge" dropdown.
Enter Data: Input the weight value and select the correct unit (kg, lbs, etc.).
Review Results: The copper wire weight to length calculator instantly updates the length in meters and feet.
Check Value: If you know the current scrap price per pound or kilo, enter it to see the total estimated value of the metal.
Key Factors That Affect Calculator Accuracy
While the math is precise, real-world factors can influence the results of any copper wire weight to length calculator:
Insulation Weight: This is the most significant factor. This calculator assumes bare copper. If you weigh insulated wire, you must account for the plastic weight (often 10-20% of the total depending on wire type like THHN vs Romex).
Copper Purity: Standard calculation uses pure copper density (8.96 g/cm³). Lower grade alloys or copper-clad aluminum (CCA) have much lower densities, meaning a copper wire weight to length calculator would underestimate the length of CCA wire.
Stranding Class: Solid core wire is 100% copper volume. Stranded wire has small air gaps between strands, effectively increasing the diameter for the same amount of copper. However, weight-to-length calculations remain accurate based on weight, regardless of stranding, provided you are weighing the metal itself.
Corrosion/Oxidation: Heavily oxidized copper may weigh slightly more due to the added oxygen mass, but this is usually negligible for general estimates.
Measurement Error: Digital scales vary in precision. A variance of 0.1 kg on a thin wire can result in a length discrepancy of several meters.
Manufacturing Tolerances: Wire is manufactured to tolerances. A "12 AWG" wire might vary slightly in actual diameter between manufacturers, affecting the exact weight per foot.
Frequently Asked Questions (FAQ)
Does this calculator work for insulated wire?
This copper wire weight to length calculator is designed for bare copper. If your wire has insulation, you must estimate the weight of the copper inside. A general rule of thumb for standard building wire is that copper makes up about 70-80% of the total weight, but stripping a sample foot is the best way to verify.
Why is density important in this calculation?
Density is the bridge between weight and volume. Without a constant density value for copper (8.96 g/cm³), it would be impossible to convert mass into physical dimensions like length.
Can I use this for other metals like Aluminum?
No. Aluminum has a density of roughly 2.70 g/cm³, which is much lighter than copper. Using this calculator for aluminum would result in a massive error. You would need a specific aluminum wire calculator.
What is AWG?
AWG stands for American Wire Gauge. It is a logarithmic standard used in North America. The larger the number, the thinner the wire. Our calculator includes standard AWG sizes from 4/0 (thickest) to 30 (thinnest).
How accurate is the result?
For solid bare copper, the result is theoretically 99.9% accurate. Real-world variances usually come from the accuracy of your scale or the purity of the copper.
Does temperature affect the weight?
Technically, volume changes with temperature (expansion), but mass (weight) remains constant. Therefore, temperature does not affect the accuracy of a weight-based calculation.
How do I calculate the weight of the spool?
The best method is to weigh an identical empty spool (tare weight). If that isn't available, standard plastic spools often have their weight stamped on them, or you can estimate based on size (e.g., small plastic spools are approx 100g).
What is the difference between solid and stranded wire for this calculator?
Since this tool calculates based on weight, the difference is minimal. 1kg of copper is 1kg of copper, whether it is one thick strand or many thin ones. The length of copper is the same, though the physical diameter of the stranded cable might be larger.
Related Tools and Internal Resources
Enhance your estimation toolkit with these related resources:
Scrap Metal Value Estimator – Determine the current market value for various scrap metals including brass and aluminum.
{related_keywords} – A guide to understanding wire gauges and ampacity ratings for electricians.
Conduit Fill Calculator – Calculate how many wires fit into specific conduit sizes based on NEC standards.
Voltage Drop Calculator – Ensure your wire length doesn't exceed voltage drop limits for your circuit.