Casting Weight Calculator
Quick Answer
For steel and iron castings, weight ≈ part volume × alloy density. Common cast densities: grey cast iron ≈ 7.2 g/cm³, ductile iron ≈ 7.1 g/cm³, carbon cast steel ≈ 7.85 g/cm³, stainless cast steel ≈ 7.75 g/cm³. Multiply net solid volume (cm³) by density for net weight; add gating, risers and machining stock for poured weight.
- Formula: weight (g) = volume (cm³) × alloy density (g/cm³)
- Grey iron: 7.2 · Ductile iron: 7.1 · Carbon steel: 7.85 · Stainless: 7.75 g/cm³
- Net vs poured: add gating, risers and machining stock for actual poured weight
- Cored holes: subtract bore/void volume before applying density
Estimate the net cast weight of a part from its shape and alloy — then get the poured (melt) weight, batch quantity and material cost. Unlike generic metal calculators, this one uses real cast-alloy densities (cast 304/316, gray and ductile iron, bronze, A356) and lets you enter a CAD volume for complex castings.
How casting weight is calculated
Weight = part volume × alloy density. Volume comes from the geometry you choose, or directly from your CAD model:
The poured weight includes the gating and feeders that are remelted — it is what actually determines melt cost. Net weight is the finished part.
Cast-alloy density reference
| Alloy | Density (g/cm³) |
|---|---|
| Carbon / low-alloy steel | 7.85 |
| Cast stainless 304 (CF8) | 7.93 |
| Cast stainless 316 (CF8M) | 7.98 |
| Gray cast iron | 7.20 |
| Ductile (nodular) iron | 7.10 |
| Bronze (general) | 8.80 |
| Yellow brass | 8.50 |
| Aluminum A356 | 2.68 |
1 g/cm³ = 1000 kg/m³ = 0.0361 lb/in³. Use a custom density for alloys not listed.
Frequently Asked Questions
How do you calculate the weight of a casting?
Multiply the part’s volume by the alloy density. Get the volume from the geometry (length, diameter, etc.) or directly from a CAD model, then multiply by the density — for example 7.85 g/cm³ for carbon steel or 7.20 for gray iron.
What is the difference between net weight and poured weight?
Net weight is the finished casting. Poured (melt) weight also includes the gating, runners and risers that feed the mould and are later remelted. Poured weight = net weight ÷ casting yield, where yield is typically 50–70% for investment casting.
What density should I use for cast stainless steel?
Cast stainless grades differ slightly from wrought: use about 7.93 g/cm³ for cast 304 (CF8) and 7.98 for cast 316 (CF8M). Generic “stainless” values from metal calculators can be off for castings.
Can I calculate weight from a CAD volume?
Yes. Switch the shape selector to “Custom Volume” and enter the volume from your CAD model in cm³ or in³; the calculator multiplies it by the alloy density. This is the most accurate option for complex castings.
Why is the actual casting heavier than calculated?
As-cast parts include machining stock, draft and tolerance, and the density assumes zero porosity. Treat the result as a close estimate and confirm with a first-article weight.
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Related Resources
Investment & Steel Casting alloy grade chart — ASTM ↔ EN ↔ GB ↔ JIS
Density and minimum properties per ASTM specification. Cross-standard equivalents are by composition/class for reference — confirm exact interchange for critical parts.
| Grade | Density (g/cm³) | Tensile (per ASTM) | Cross-standard equivalent | PREN |
|---|---|---|---|---|
| Carbon Steel — WCB (ASTM A216) | 7.85 | 485–655 MPa (70–95 ksi) | EN 1.0619 GP240GH / GB ZG230-450 | — |
| Carbon Steel — WCC (ASTM A216) | 7.85 | 485–655 MPa | EN 1.0625 / GB ZG270-500 | — |
| Stainless CF8 — cast 304 (A351) | 7.75 | 485 MPa min (70 ksi) | EN 1.4308 / GB ZG07Cr19Ni9 | ≈ 18–20 |
| Stainless CF8M — cast 316 (A351) | 7.75 | 485 MPa min | EN 1.4408 / GB ZG07Cr19Ni12Mo2 | ≈ 24–26 |
| Stainless CF3M — cast 316L (A351) | 7.75 | 485 MPa min | EN 1.4409 / GB ZG03Cr19Ni12Mo2 | ≈ 24–26 |
| Duplex CD4MCu / ~2205 (A890) | 7.8 | 620 MPa min | ≈ 2205 / EN 1.4517 | ≈ 34–40 |
Frequently Asked Questions
How do you calculate the weight of a casting?
Casting weight = part volume × material density. Get the volume from your 3D/CAD model, select the alloy for its density (investment & steel casting grades shown above), multiply to get grams, then divide by 1000 for kilograms. Add gating, risers and machining allowance for the as-cast weight.
What is PREN and why does it matter for stainless steel castings?
PREN (Pitting Resistance Equivalent Number = %Cr + 3.3×%Mo + 16×%N) ranks an alloy's resistance to chloride pitting. CF8 (cast 304) ≈ 18–20, CF8M (cast 316) ≈ 24–26, and duplex CD4MCu/2205 ≈ 34–40 — the higher the PREN, the better for seawater, brine and aggressive valve/pump service.
Why casting weight matters before you cut a pattern
Casting weight is one of the first numbers that drives a foundry quote. It sets the volume of metal that has to be melted and poured, which in turn influences material cost, furnace and ladle planning, gating and riser sizing, machining stock removal and even outbound freight. Getting a reliable weight early — ideally before a pattern or tooling is committed — lets you sanity-check a design, compare alloys and avoid expensive surprises once metal is flowing.
The calculation itself is simple: casting weight (kg) = part volume (cm³) × material density (g/cm³) ÷ 1000. The volume comes from your drawing or 3D/CAD mass properties; the density comes from the cast alloy you choose. Because density varies by material, the same part swings noticeably in weight depending on what it is poured in — a part in grey cast iron (≈7.15 g/cm³) weighs roughly 9–10% less than the identical geometry in carbon cast steel (≈7.85 g/cm³). That delta feeds straight into per-piece cost, so the alloy decision and the weight estimate are best made together.
This tool gives a fast, transparent material-weight estimate. For an as-cast or finished weight you still add gating, risers and machining allowance, and subtract any cored voids — see the worked examples below, and send your drawing through Get a quote when you need an exact figure.
Worked examples
1. Flat plate in grey cast iron
A rectangular plate measuring 200 × 150 × 40 mm. Convert to centimetres: 20 × 15 × 4 = 1,200 cm³. Grey cast iron density ≈ 7.15 g/cm³.
Weight = 1,200 × 7.15 ÷ 1000 = 8.58 kg (about 18.9 lb). This is the solid material weight; add gating, risers and any machining stock for the as-cast weight.
2. Same plate, swapped to carbon cast steel
Take the identical 1,200 cm³ plate but pour it in carbon cast steel (WCB, ≈7.85 g/cm³) instead of grey iron.
Weight = 1,200 × 7.85 ÷ 1000 = 9.42 kg (about 20.8 lb). The geometry never changed, yet the part is 0.84 kg (~10%) heavier simply because steel is denser — a clear illustration of why the alloy choice and the weight estimate belong together when budgeting a part.
3. Block with a cored hole (subtract the bore)
A bracket block 150 × 100 × 60 mm in ductile (nodular) iron, ≈7.10 g/cm³, with a cored through-bore of 50 mm diameter, 60 mm deep. Cored voids do not contain metal, so subtract their volume.
Solid block = 15 × 10 × 6 = 900 cm³. Bore volume = π × (2.5 cm)² × 6 cm ≈ 117.8 cm³. Net volume = 900 − 117.8 = 782.2 cm³.
Weight = 782.2 × 7.10 ÷ 1000 ≈ 5.55 kg (about 12.2 lb). Always net out cored holes, pockets and bores — ignoring them over-estimates both weight and material cost.
Cast metal density reference
Indicative densities for the main cast iron and cast steel families this foundry pours. Use these in the calculator (or as a quick desk reference) and confirm the exact figure against your alloy specification for critical parts.| Cast metal | Density (g/cm³) | Typical use |
|---|---|---|
| Grey cast iron | 7.15 | Machine bases, housings, brackets, manifolds — good damping and machinability where high strength is not required. |
| Ductile (nodular) iron | 7.10 | Pump bodies, valve components, gears, structural parts needing higher strength and ductility than grey iron. |
| Malleable iron | 7.30 | Pipe fittings, small high-strength brackets and linkages where toughness and impact resistance matter. |
| Carbon cast steel | 7.85 | Pressure-containing valve/pump bodies and load-bearing parts (e.g. WCB) needing weldability and strength. |
| Stainless cast steel | 7.75 | Corrosion-resistant valve, pump and process parts (e.g. CF8/CF8M) for water, chemical and marine service. |
Values are typical/indicative. Actual density varies slightly with chemistry, graphite form and casting soundness; round-off in published tables also differs by source. Treat these as planning figures, not certified material data.
Who uses this calculator
Quick casting-weight estimates are useful across the sectors a sand and steel foundry serves: automotive components, agricultural and construction machinery, pumps and valves, municipal and waterworks hardware, rail fittings and general engineering parts. Within those projects the tool tends to land in the hands of buyers and procurement teams pricing a part, design engineers checking that a concept hits its weight and material budget, and estimators building a quote. Each gets a fast, defensible material weight to work from — then sends the drawing to confirm gating, machining stock and cored features. See related work in valve casting, pump parts, automotive parts and industrial machinery.
How reliable is this estimate?
We build this calculator to be transparent rather than a black box. It applies one well-known relationship — weight = volume × density ÷ 1000 — using standard, published densities for each cast iron and cast steel family. There are no hidden multipliers and no fabricated benchmarks: what you put in (volume and density) is exactly what drives the result. As a working foundry we pour iron and steel castings daily, so we treat these figures the way we treat them in production — as a starting point that always gets confirmed against the actual pattern and drawing.
- Results are indicative material weight only — they assume a fully dense, solid volume.
- Real castings differ because of shrinkage, draft angles, fillets and radii, and machining allowance that are not in a nominal dimension box.
- Subtract cored holes, pockets and bores; the calculator can't see geometry it isn't told about.
- Densities are typical values and vary slightly with chemistry and casting soundness — confirm against your alloy spec for critical parts.
- For an as-cast or quoted weight, gating and risers are added on top — send your drawing and we'll work it out exactly.
Glossary
- Machining allowance
- Extra metal added to surfaces that will be machined after casting, so there is stock to cut away to the finished dimension. It adds to the as-cast weight beyond the nominal part volume.
- Shrinkage
- Metal contracts as it solidifies and cools. Pattern dimensions are scaled up by a shrinkage factor so the finished casting reaches target size; it also affects where risers are needed to feed the part.
- Core
- A shaped insert (often sand) placed in the mould to form internal cavities, holes or passages. Cored volume contains no metal, so it must be subtracted from the casting weight.
- Casting yield
- The ratio of finished casting weight to the total metal poured (part plus gating and risers), expressed as a percentage. Higher yield means less metal returned as scrap and reprocessed.
Why casting weight matters before you cut a pattern
Casting weight is one of the first numbers that drives a foundry quote. It sets the volume of metal that has to be melted and poured, which in turn influences material cost, furnace and ladle planning, gating and riser sizing, machining stock removal and even outbound freight. Getting a reliable weight early — ideally before a pattern or tooling is committed — lets you sanity-check a design, compare alloys and avoid expensive surprises once metal is flowing.
The calculation itself is simple: casting weight (kg) = part volume (cm³) × material density (g/cm³) ÷ 1000. The volume comes from your drawing or 3D/CAD mass properties; the density comes from the cast alloy you choose. Because density varies by material, the same part swings noticeably in weight depending on what it is poured in — a part in grey cast iron (≈7.15 g/cm³) weighs roughly 9–10% less than the identical geometry in carbon cast steel (≈7.85 g/cm³). That delta feeds straight into per-piece cost, so the alloy decision and the weight estimate are best made together.
This tool gives a fast, transparent material-weight estimate. For an as-cast or finished weight you still add gating, risers and machining allowance, and subtract any cored voids — see the worked examples below, and send your drawing through Get a quote when you need an exact figure.
Worked examples
1. Flat plate in grey cast iron
A rectangular plate measuring 200 × 150 × 40 mm. Convert to centimetres: 20 × 15 × 4 = 1,200 cm³. Grey cast iron density ≈ 7.15 g/cm³.
Weight = 1,200 × 7.15 ÷ 1000 = 8.58 kg (about 18.9 lb). This is the solid material weight; add gating, risers and any machining stock for the as-cast weight.
2. Same plate, swapped to carbon cast steel
Take the identical 1,200 cm³ plate but pour it in carbon cast steel (WCB, ≈7.85 g/cm³) instead of grey iron.
Weight = 1,200 × 7.85 ÷ 1000 = 9.42 kg (about 20.8 lb). The geometry never changed, yet the part is 0.84 kg (~10%) heavier simply because steel is denser — a clear illustration of why the alloy choice and the weight estimate belong together when budgeting a part.
3. Block with a cored hole (subtract the bore)
A bracket block 150 × 100 × 60 mm in ductile (nodular) iron, ≈7.10 g/cm³, with a cored through-bore of 50 mm diameter, 60 mm deep. Cored voids do not contain metal, so subtract their volume.
Solid block = 15 × 10 × 6 = 900 cm³. Bore volume = π × (2.5 cm)² × 6 cm ≈ 117.8 cm³. Net volume = 900 − 117.8 = 782.2 cm³.
Weight = 782.2 × 7.10 ÷ 1000 ≈ 5.55 kg (about 12.2 lb). Always net out cored holes, pockets and bores — ignoring them over-estimates both weight and material cost.
Cast metal density reference
Indicative densities for the main cast iron and cast steel families this foundry pours. Use these in the calculator (or as a quick desk reference) and confirm the exact figure against your alloy specification for critical parts.| Cast metal | Density (g/cm³) | Typical use |
|---|---|---|
| Grey cast iron | 7.15 | Machine bases, housings, brackets, manifolds — good damping and machinability where high strength is not required. |
| Ductile (nodular) iron | 7.10 | Pump bodies, valve components, gears, structural parts needing higher strength and ductility than grey iron. |
| Malleable iron | 7.30 | Pipe fittings, small high-strength brackets and linkages where toughness and impact resistance matter. |
| Carbon cast steel | 7.85 | Pressure-containing valve/pump bodies and load-bearing parts (e.g. WCB) needing weldability and strength. |
| Stainless cast steel | 7.75 | Corrosion-resistant valve, pump and process parts (e.g. CF8/CF8M) for water, chemical and marine service. |
Values are typical/indicative. Actual density varies slightly with chemistry, graphite form and casting soundness; round-off in published tables also differs by source. Treat these as planning figures, not certified material data.
Who uses this calculator
Quick casting-weight estimates are useful across the sectors a sand and steel foundry serves: automotive components, agricultural and construction machinery, pumps and valves, municipal and waterworks hardware, rail fittings and general engineering parts. Within those projects the tool tends to land in the hands of buyers and procurement teams pricing a part, design engineers checking that a concept hits its weight and material budget, and estimators building a quote. Each gets a fast, defensible material weight to work from — then sends the drawing to confirm gating, machining stock and cored features. See related work in valve casting, pump parts, automotive parts and industrial machinery.
How reliable is this estimate?
We build this calculator to be transparent rather than a black box. It applies one well-known relationship — weight = volume × density ÷ 1000 — using standard, published densities for each cast iron and cast steel family. There are no hidden multipliers and no fabricated benchmarks: what you put in (volume and density) is exactly what drives the result. As a working foundry we pour iron and steel castings daily, so we treat these figures the way we treat them in production — as a starting point that always gets confirmed against the actual pattern and drawing.
- Results are indicative material weight only — they assume a fully dense, solid volume.
- Real castings differ because of shrinkage, draft angles, fillets and radii, and machining allowance that are not in a nominal dimension box.
- Subtract cored holes, pockets and bores; the calculator can't see geometry it isn't told about.
- Densities are typical values and vary slightly with chemistry and casting soundness — confirm against your alloy spec for critical parts.
- For an as-cast or quoted weight, gating and risers are added on top — send your drawing and we'll work it out exactly.
Glossary
- Machining allowance
- Extra metal added to surfaces that will be machined after casting, so there is stock to cut away to the finished dimension. It adds to the as-cast weight beyond the nominal part volume.
- Shrinkage
- Metal contracts as it solidifies and cools. Pattern dimensions are scaled up by a shrinkage factor so the finished casting reaches target size; it also affects where risers are needed to feed the part.
- Core
- A shaped insert (often sand) placed in the mould to form internal cavities, holes or passages. Cored volume contains no metal, so it must be subtracted from the casting weight.
- Casting yield
- The ratio of finished casting weight to the total metal poured (part plus gating and risers), expressed as a percentage. Higher yield means less metal returned as scrap and reprocessed.