Calculator Inputs
Example Data Table
| Method | Material | Input Summary | Gross Weight Per Coil | Total Weight |
|---|---|---|---|---|
| Geometry | Carbon Steel | 0.8 mm × 1250 mm, ID 508 mm, OD 1500 mm, qty 2 | 15,188.57 kg | 30,377.14 kg |
| Geometry | Carbon Steel | 1.2 mm × 1000 mm, ID 508 mm, OD 1800 mm, qty 1 | 18,287.32 kg | 18,287.32 kg |
| Strip | Carbon Steel | 1.5 mm × 1200 mm, length 850 m, qty 1 | 12,250.71 kg | 12,250.71 kg |
These examples help estimators verify typical results before using project-specific values.
Formula Used
The calculator supports two practical methods. The geometry method estimates a wound coil from diameters. The strip method calculates weight from thickness, width, and strip length.
1) Geometry Method
Annulus Area = π / 4 × (OD² − ID²)
Effective Volume = Annulus Area × Width × Packing Factor
Net Coil Weight = Effective Volume × Density
Gross Coil Weight = Net Coil Weight × (1 + Scrap % / 100)
Estimated Strip Length = Packing Factor × π × (OD² − ID²) / (4 × Thickness)
2) Strip Method
Volume = Thickness × Width × Strip Length
Net Coil Weight = Volume × Density
Gross Coil Weight = Net Coil Weight × (1 + Scrap % / 100)
Total Weight = Gross Coil Weight × Quantity
Use consistent units. The script converts all values internally before calculation, then returns the chosen output units.
How to Use This Calculator
- Select the calculation method that matches your available data.
- Choose a material preset or enter a custom density.
- Pick your dimension, length, and output weight units.
- Enter thickness and width for both methods.
- For geometry mode, enter inner diameter, outer diameter, and packing factor.
- For strip mode, enter the strip length directly.
- Add quantity and scrap allowance if needed.
- Press calculate to view the result summary, graph, and downloadable report.
FAQs
1) Which method should I use?
Use geometry mode when you know inner diameter, outer diameter, thickness, and width. Use strip mode when you already know the strip length. Both methods estimate the same physical mass, but they start from different known inputs.
2) Why does packing factor matter?
Packing factor adjusts for the practical winding condition of the coil. A perfectly solid annulus is theoretical. Real coils can have slight gaps, coating effects, or winding looseness, so a factor like 0.95 to 0.99 often gives more realistic estimates.
3) Does scrap percentage change unit weight?
It changes the gross planning weight, not the physical net steel mass. Fabricators often add scrap or process allowance to cover trimming, losses, rejects, and handling needs during procurement or estimating.
4) Can I use this for stainless or galvanized material?
Yes. The calculator includes presets for carbon, stainless, galvanized, and electrical steel. You can also select custom density if your project specification or supplier data sheet lists a different material density.
5) Why is thickness needed in geometry mode?
Thickness is required to estimate strip length from the coil’s wound geometry. Weight can come from annulus volume and density, but strip length needs the strip thickness to convert the wound buildup into a linear length estimate.
6) Are the results suitable for purchasing decisions?
They are suitable for estimating, planning, and checking supplier data. For commercial transactions, confirm final values with certified mill documents, actual measured dimensions, coating details, and contractual tolerances.
7) Can I export the result?
Yes. The page includes CSV export for result data and the example table, plus a PDF summary export. This helps estimators share project assumptions, report values, or keep a documented calculation record.
8) What is the difference between net and gross weight?
Net weight is the calculated steel mass before any allowance. Gross weight in this calculator includes the chosen scrap or process percentage, making it more useful for ordering, cutting plans, and project budgeting.