How the calculator works
This free metal weight calculator (and material weight calculator) multiplies volume by density. Mild steel is 7850 kg/m³. No sign-up. Every dimension is converted to millimetres, volume is computed in cubic millimetres, then the material density (g/cm³) is applied and the result is reported in kilograms, grams, pounds, ounces or tonnes — a metal weight calculator in kg by default. Dedicated pages: steel weight calculator, stainless steel weight calculator, copper and brass. Need the weight of an actual CAD model? Use the STEP, STP, IGES & IGS weight calculator.
Formula
W = V × ρ
ρ_steel = 7.85 g/cm³ = 7850 kg/m³
Plate: V = L × W × T
Round bar: V = π r² L
Tube: V = π L (Rₒ² − Rᵢ²)
Example — 10 mm mild steel plate, 2 m × 1 m
V = 2 × 1 × 0.010 = 0.020 m³
W = 0.020 × 7850 = 157 kg
Worked examples — steel plate, bar and tube
Unit weight of steel is 7850 kg/m³. Load any row in the calculator above, or use it as a steel plate weight, round-bar kg/m, or metal tube weight check.
| Example | Weight |
|---|---|
| 20 mm steel plate, 1 m × 1 m | 157 kg |
| Ø20 steel round bar, 1 m | 2.47 kg |
| 100 × 50 × 10 mm steel plate | 0.39 kg |
| Steel tube Ø50 × 3 mm × 1 m | 3.48 kg |
Shapes this calculator covers
Use it as a sheet metal weight calculator (sheet uses the same L × W × T formula as plate), a square bar or rectangular bar weight calculator, a cylinder or disc weight calculator, a tube or pipe weight calculator, or a general bar weight calculator. Typed dimensions also cover part weight and component weight — a metal mass calculator / material mass calculator / weight from dimensions calculator for take-offs.
- Plate · length × width × thickness
- Sheet · length × width × thickness
- Round Bar · diameter × length
- Square Bar · side × length
- Rectangular Bar · width × height × length
- Tube · od × wall × length
- Pipe · od × wall × length
- Cylinder · diameter × length
- Disc · diameter × thickness
- Custom box · length × width × height
Common material densities
Figures match common stockholder and workshop practice, not every mill certificate. Stainless 304/316 is 8.00 g/cm³, aluminium 6061 is 2.70, 7075 is 2.81, copper 8.96, brass 8.50. The same densities power an EN8, EN19, EN24, D2 steel or H13 steel weight calculator, plus bronze, cast iron, nylon and Delrin / acetal take-offs, without a separate page for each alloy. A Delrin weight calculator is this page: Delrin / Acetal is 1.41 g/cm³ and POM acetal is 1.40. Plastics from the shop chart sit on the same menu: PP 0.90, HDPE 0.95, unfilled ABS 1.05, PMMA 1.17, polycarbonate 1.20, POM acetal 1.40 and rigid PVC 1.40. Glass-filled nylon and POM are heavier (Nylon 66 30% GF 1.40, POM GF30 1.60, Nylon 66 60% GF 1.70). Where the chart gives a range — filled PP, Nylon 66, TPE, TPU — the menu uses the midpoint and the note shows the range. Enter a custom density when a drawing or cert specifies one.
| Material | Group | Density | Notes |
|---|---|---|---|
| Mild Steel | Steel | 7.85 g/cm³ | Typical shop value for S275 / A36 class carbon steel. |
| Carbon Steel | Steel | 7.85 g/cm³ | General carbon steels; similar mass to mild steel for estimating. |
| Stainless Steel 304 | Stainless | 8 g/cm³ | Austenitic 18/8 stainless. Slightly denser than carbon steel. |
| Stainless Steel 316 | Stainless | 8 g/cm³ | Marine-grade 18/10/2 stainless; use 8.00 g/cm³ for estimates. |
| EN8 | Steel | 7.85 g/cm³ | 080M40 medium-carbon steel, common for shafts and pins. |
| EN19 | Steel | 7.85 g/cm³ | 709M40 alloy steel used for high-tensile shafts and gears. |
| EN24 | Steel | 7.85 g/cm³ | 817M40 nickel-chromium-molybdenum steel. |
| D2 | Tool steel | 7.7 g/cm³ | High-carbon, high-chromium cold-work tool steel. |
| H13 | Tool steel | 7.8 g/cm³ | Hot-work tool steel for dies and moulds. |
| Aluminium | Aluminium | 2.7 g/cm³ | Commercially pure / general aluminium, ~2.70 g/cm³. |
| Aluminium 6061 | Aluminium | 2.7 g/cm³ | The most common structural aluminium alloy. |
| Aluminium 7075 | Aluminium | 2.81 g/cm³ | Zinc-alloyed aerospace grade; a little denser than 6061. |
| Copper | Copper alloys | 8.96 g/cm³ | Electrolytic copper. Heavy — nearly 9 g/cm³. |
| Brass | Copper alloys | 8.5 g/cm³ | Typical 60/40 or 70/30 brass. Alloys range ~8.4–8.7. |
| Bronze | Copper alloys | 8.8 g/cm³ | Tin bronze around 8.7–8.9 g/cm³ depending on tin content. |
| Titanium | Other metals | 4.51 g/cm³ | Commercially pure Ti; Ti-6Al-4V is about 4.43 g/cm³. |
| Cast Iron | Other metals | 7.2 g/cm³ | Grey iron ~7.1–7.3. Ductile iron is closer to 7.1. |
| Nylon | Plastics | 1.14 g/cm³ | Generic unfilled nylon. Shop chart puts Nylon 66 at 1.14–1.15 g/cm³; Nylon 6 is 1.13. |
| Nylon 6 | Plastics | 1.13 g/cm³ | Unfilled PA6. Shop chart 1.13 g/cm³. |
| Nylon 66 | Plastics | 1.15 g/cm³ | Unfilled PA66. Shop range 1.14–1.15 g/cm³; calculator uses 1.15. |
| Nylon 6 30% GF | Plastics | 1.36 g/cm³ | PA6 with 30% glass. Shop chart 1.36 g/cm³. |
| Nylon 66 30% GF | Plastics | 1.4 g/cm³ | PA66 with 30% glass. Shop chart 1.40 g/cm³. |
| Nylon 66 40% GF | Plastics | 1.48 g/cm³ | PA66 with 40% glass. Shop range 1.45–1.50 g/cm³; calculator uses 1.48. |
| Nylon 66 60% GF | Plastics | 1.7 g/cm³ | PA66 with 60% glass. Shop chart 1.70 g/cm³. |
| PA46 | Plastics | 1.4 g/cm³ | Unfilled PA46. Shop chart 1.40 g/cm³. |
| Delrin / Acetal | Plastics | 1.41 g/cm³ | POM homopolymer, 1.41 g/cm³. Unfilled POM on the shop chart is 1.40. |
| POM / Acetal | Plastics | 1.4 g/cm³ | Unfilled POM, the copolymer next to Delrin. Shop chart 1.40 g/cm³. Delrin homopolymer is 1.41. |
| POM GF30 | Plastics | 1.6 g/cm³ | POM with 30% glass. Shop chart 1.60 g/cm³. |
| ABS | Plastics | 1.05 g/cm³ | Unfilled ABS. Shop chart 1.05 g/cm³. ABS 30% GF is 1.30. |
| ABS 30% GF | Plastics | 1.3 g/cm³ | ABS with 30% glass. Shop chart 1.30 g/cm³. |
| PVC | Plastics | 1.4 g/cm³ | Rigid PVC. Shop chart 1.40 g/cm³. Plasticised grades are lighter. |
| PP | Plastics | 0.9 g/cm³ | Unfilled polypropylene. Shop chart 0.90 g/cm³. |
| PP Filled | Plastics | 1.16 g/cm³ | Filled polypropylene. Shop range 1.12–1.20 g/cm³; calculator uses 1.16. |
| HDPE | Plastics | 0.95 g/cm³ | High-density polyethylene. Shop chart 0.95 g/cm³. |
| PMMA (Acrylic) | Plastics | 1.17 g/cm³ | Acrylic. Shop chart 1.17 g/cm³. |
| Polycarbonate | Plastics | 1.2 g/cm³ | Unfilled PC. Shop chart 1.20 g/cm³. |
| PC+ABS | Plastics | 1.15 g/cm³ | Polycarbonate / ABS blend. Shop chart 1.15 g/cm³. |
| PC-PBT | Plastics | 1.35 g/cm³ | Unfilled PC-PBT. Shop chart 1.35 g/cm³. |
| PC-PBT 30% GF | Plastics | 1.5 g/cm³ | PC-PBT with 30% glass. Shop chart 1.50 g/cm³. |
| TPE | Plastics | 1 g/cm³ | Thermoplastic elastomer. Shop range 0.80–1.20 g/cm³; calculator uses 1.00. |
| TPU | Plastics | 1.28 g/cm³ | Thermoplastic polyurethane. Shop range 1.20–1.35 g/cm³; calculator uses 1.28. |
How a toolroom estimates weight before machining
Before we order plate or bar for a die, we calculate volume × density the same way this page does. Mild steel at 7.85 g/cm³ is the default take-off; stainless, copper and titanium need their own density or the quote is wrong. When the customer sends a STEP, STP, IGES or IGS file instead of a drawing, choose that mode and weigh the solid.
Unit weight of steel, plate and tube
The unit weight of steel used here is 7850 kg/m³ (7.85 g/cm³) — the same figure as a mild steel or carbon steel take-off, and the answer to “what is the unit weight of steel in kg m3”. Steel plate weights are L × W × T × 7850. Steel weight per metre of round bar is π/4 × D² × 7850 with L = 1 m (Ø20 mm bar ≈ 2.47 kg/m) — a metre to kg converter for steel bar. Weight of steel per cubic cm is 7.85 g; per cubic inch about 0.283 lb. A metal tube weight calculator is the hollow-cylinder form: enter OD, wall and length. Results are in kg by default; switch to lb if the quote is imperial. This page is also a mass of steel calculator when you only have dimensions.
Weight by metal
- Steel weight calculator · 7.85 g/cm³
- Aluminium weight calculator · 2.7 g/cm³
- Copper weight calculator · 8.96 g/cm³
- Stainless steel weight calculator · 8 g/cm³
- Brass weight calculator · 8.5 g/cm³
- Titanium weight calculator · 4.51 g/cm³
Weight from a STEP, STP, IGES or IGS model
Choose From a STEP, STP, IGES or IGS file and drop a .STEP, .STP, .IGES or .IGS. The solid is opened in your browser, the volume is measured, then multiplied by the same densities as plate and bar. Turn on Measure to check a length, diameter, radius or angle on the 3D view. Treat the mass as a quotation estimate. A dedicated STEP, STP, IGES & IGS weight calculator calculates CAD mass and volume on its own page. That page also weighs a SolidWorks .SLDPRT or .prt, a .3ds mesh, and a Rhino .3dm. To view the model and check dimensions, use the CAD Viewer.
Need to convert the result into pounds or tonnes, or check a length in inches? Open the unit converter.