Calculate coil weight, width, length, thickness, or density from the other four values using mm, cm, m, in, ft, kg/m³, lb/ft³, and weight units to get the missing measurement or mass.
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Coil Weight Formula
The calculator treats the coil as a flat strip of material with a known width, length, thickness, and density. It converts all length inputs to meters, density to kg/m³, and weight to kilograms before calculating the missing value.
CW = W*L*T*rho
Rearranged formulas for the other fields:
W = CW/(L*T*rho)
L = CW/(W*T*rho)
T = CW/(W*L*rho)
rho = CW/(W*L*T)
- CW = coil weight, in kilograms before output conversion
- W = coil width, in meters before output conversion
- L = coil length, in meters before output conversion
- T = coil thickness, in meters before output conversion
- rho = material density, in kg/m³ before output conversion
To calculate coil weight, enter width, length, thickness, and density, then leave coil weight blank. To solve for width, length, thickness, or density, enter the other four values and leave the unknown field blank. The same volume and density relationship is used in every case.
Common Coil Material Densities
Use a density that matches the actual material grade when possible. The values below are typical reference values for common coil materials.
| Material | Density kg/m³ | Density lb/ft³ |
|---|---|---|
| Carbon steel | 7,850 | 490 |
| Stainless steel | 7,900 to 8,000 | 493 to 499 |
| Aluminum | 2,700 | 169 |
| Copper | 8,960 | 559 |
| Brass | 8,400 to 8,700 | 524 to 543 |
Weight Unit Conversions Used for Coil Results
| Unit | Equivalent in kg | Equivalent from 1 kg |
|---|---|---|
| Kilogram | 1 | 1 kg |
| Pound | 0.453592 | 2.20462 lb |
| Short ton | 907.185 | 0.00110231 short tons |
| Metric ton | 1,000 | 0.001 metric tons |
Example Calculations
Example 1: Calculate coil weight
You have a steel coil with a width of 1.2 m, length of 500 m, thickness of 0.8 mm, and density of 7,850 kg/m³.
Convert thickness to meters:
0.8 mm = 0.0008 m
Apply the coil weight formula:
CW = 1.2*500*0.0008*7850 = 3768 kg
The coil weight is 3,768 kg, or 3.768 metric tons.
Example 2: Calculate coil length
You have an aluminum coil weighing 2,000 kg. The width is 1 m, the thickness is 1.5 mm, and the density is 2,700 kg/m³.
Convert thickness to meters:
1.5 mm = 0.0015 m
Use the length formula:
L = 2000/(1*0.0015*2700) = 493.8272 m
The coil length is about 493.83 m.
FAQ
Does this calculate weight from coil outside diameter and inside diameter?
No. This calculator uses width, length, thickness, and material density. If you only have outside diameter, inside diameter, and width, you need a different coil weight formula based on annular volume.
Why does thickness need to be entered carefully?
Thickness has a large effect on the result because coil weight is directly proportional to thickness. For example, doubling the thickness doubles the calculated weight if width, length, and density stay the same. Make sure millimeters, inches, and other thickness units are selected correctly.
What density should you use for steel coil?
For general carbon steel, 7,850 kg/m³ is commonly used. Stainless steel is often slightly higher, usually around 7,900 to 8,000 kg/m³ depending on grade. If the material specification gives an exact density, use that value for the most accurate result.
