Multi-Item Bill of Materials
| Item | Material | Shape | Volume/piece (m³) | Quantity | Waste % | Price/kg | Weight kg | Cost |
|---|
Formula Used
The calculator uses weight equals volume multiplied by density. Every dimension is converted into meters before a shape formula is applied. The resulting volume is measured in cubic meters, while density is normalized to kilograms per cubic meter. This produces kilograms before the answer is converted into the selected display unit.
How to Use This Calculator
Select the required calculation mode, material, and stock shape. Choose a standard preset or enter dimensions with independent units. Add production quantity, extra pieces, waste, cutting, machining, kerf, trimming, and safety allowances. Optional sections estimate coating weight, filled-pipe weight, density adjustments, tolerance ranges, and purchasing cost. Submit the form to display results above the inputs.
Choosing a material density
Material databases provide planning values, not certified batch measurements. Alloy chemistry, porosity, moisture, fillers, and temperature can change actual density. Use the override option when a supplier certificate, laboratory result, or product specification gives a more appropriate value.
Theoretical versus actual weight
Theoretical weight assumes perfect geometry. Rolled plate thickness, tube wall thickness, structural corner radii, seams, scale, coatings, and dimensional tolerances cause real stock to differ. Use certified section tables whenever a contract or regulated design requires official mass per length.
Waste and purchasing allowance
General waste represents material bought but not included in finished parts. Cutting allowance covers setup and squaring. Kerf loss accounts for saw, laser, plasma, or waterjet removal. Machining allowance reserves stock for milling, turning, grinding, and finishing. Reusable scrap reduces only the allowance portion.
Coating and galvanizing weight
Coating mass is estimated from external surface area, coating thickness, and coating density. The approximation is useful for paint, plating, galvanizing, lining, and insulation. It assumes uniform thickness and does not model drips, overlaps, absorption, edge buildup, or incomplete coverage.
Pipe and tube fill calculations
For round hollow sections, internal volume is calculated from the inner diameter and length. Multiplying that volume by fill density gives content mass. The option can represent water, oil, grout, concrete, resin, insulation, or another known fill material.
Coil calculations
A strip coil is modeled as an annular cylinder. Outer diameter, inner diameter, and strip width determine material volume. Dividing volume by strip width and thickness estimates uncoiled length. Air gaps, winding tension, protective layers, and ovality can change actual results.
Cost estimation
Choose the price basis used by the supplier. The calculator supports price per kilogram, tonne, pound, or piece. Supplier discount is deducted from material cost. Processing, freight, and handling are added next, and tax is applied to the resulting subtotal.
Tolerance range
The displayed range combines entered dimensional and density tolerances as a simple planning percentage. It is not a statistical uncertainty calculation. Safety-critical work should use controlled drawings, calibrated measurement, certified materials, and qualified engineering review.
Material comparison
Comparison mode applies a second material density to the same geometry and quantity. It shows the weight difference and percentage change. This supports early-stage substitution studies, but strength, stiffness, corrosion, fire behavior, manufacturability, and cost must also be checked.
Reverse calculations
Reverse modes estimate volume from weight, length from weight and cross-sectional area, quantity from available weight, density from known weight and volume, or plate thickness from target weight. These modes rely on the same normalized SI-unit workflow as forward calculations.
Common Material Density Table
| Material | Density kg/m³ | Category | Typical planning use |
|---|---|---|---|
| Mild Steel | 7,850 | Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Carbon Steel | 7,850 | Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Stainless Steel 304 | 7,930 | Stainless Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Stainless Steel 316 | 8,000 | Stainless Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Stainless Steel 410 | 7,750 | Stainless Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Tool Steel | 7,850 | Steel | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Gray Cast Iron | 7,200 | Iron | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Ductile Iron | 7,100 | Iron | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Aluminum 1050 | 2,710 | Aluminum | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Aluminum 6061 | 2,700 | Aluminum | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Aluminum 7075 | 2,810 | Aluminum | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Copper | 8,960 | Copper Alloy | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Brass | 8,500 | Copper Alloy | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Bronze | 8,800 | Copper Alloy | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Phosphor Bronze | 8,800 | Copper Alloy | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Titanium Grade 2 | 4,510 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Titanium Grade 5 | 4,430 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Zinc | 7,140 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Lead | 11,340 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Nickel | 8,908 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Magnesium | 1,740 | Special Metal | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Inconel 625 | 8,440 | Nickel Alloy | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| HDPE Plastic | 950 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| LDPE Plastic | 920 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Rigid PVC | 1,400 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| ABS Plastic | 1,040 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Nylon 6 | 1,130 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Polycarbonate | 1,200 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| PTFE | 2,200 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Acrylic / PMMA | 1,180 | Plastic | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Natural Rubber | 930 | Rubber | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Soda-Lime Glass | 2,500 | Glass | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Normal Concrete | 2,400 | Construction | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Common Brick | 1,900 | Construction | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Granite | 2,700 | Stone | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Marble | 2,710 | Stone | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Oak Timber | 700 | Wood | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Pine Timber | 500 | Wood | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Plywood | 600 | Wood | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
| Custom Material | 1,000 | Custom | Use as a theoretical starting value and verify the relevant grade or supplier specification. |
Frequently Asked Questions
Is weight the same as mass here?
The outputs are engineering mass values in kilograms, pounds, tonnes, and related units. Purchasing practice commonly calls these values weight.
Why can a supplier value differ?
Stock tolerances, density variation, seams, corner radii, coatings, moisture, scale, and manufacturing processes can change actual mass.
Can the calculator estimate weight per length?
Yes. Bars, wires, pipes, tubes, and structural sections show kilograms per meter when a valid length is entered.
Can it calculate unknown length?
Yes. Select length from weight, enter a target weight, and provide a shape with a valid cross-sectional area.
How are hollow sections handled?
Round, square, and rectangular hollow profiles subtract their internal area from the external area before multiplying by length.
Can I use custom density?
Yes. Select custom material or enable density override and enter density in any supported density unit.
Does it replace structural section tables?
No. Certified manufacturer or standards-based tables should control when official section properties or contract quantities are required.
Are saved projects uploaded?
No. Saved form projects and BOM records use browser local storage on the current device.