Material Density Table for Weight & Cost Estimation
Density of 20 CNC materials in g/cm³ and lb/in³ with the weight of a 100 × 100 × 10 mm blank, plus the formulas to turn drawing dimensions into material cost.
Density and reference-blank weight by material
| Material | Designation | Density (g/cm³) | Density (lb/in³) | Blank weight, 100 × 100 × 10 mm (kg) | Source |
|---|---|---|---|---|---|
| Aluminium 1060 | UNS A91060 | 2.705 | 0.09772 | 0.271 | MatWeb — Aluminum 1060-H12 |
| Aluminium 6061-T6 / T651 | UNS A96061 | 2.70 | 0.0975 | 0.270 | MatWeb — Aluminum 6061-T4; 6061-T451 |
| Aluminium 7075-T6 / T651 | UNS A97075 | 2.81 | 0.102 | 0.281 | MatWeb — Aluminum 7075-O |
| Copper, ETP | UNS C11000 | 8.89 | 0.321 | 0.889 | MatWeb — ETP copper, UNS C11000 |
| Brass, free-cutting | UNS C36000 | 8.50 | 0.307 | 0.850 | MatWeb — free-cutting brass C36000, H02 |
| Carbon steel 1045 | UNS G10450 | 7.87 | 0.284 | 0.787 | MatWeb — AISI 1045, hot rolled / cold drawn |
| Alloy steel 4140 | UNS G41400 | 7.85 | 0.284 | 0.785 | MatWeb — AISI 4140, normalized / quenched and tempered |
| Stainless steel 304 | UNS S30400 | 7.93 | 0.286 | 0.793 | ASTM A240/A276 + EN 10088-2 (1.4301) + JIS G4304 (three agreeing sources) |
| Stainless steel 316 | UNS S31600 | 7.92 | 0.286 | 0.792 | MatWeb — austenitic stainless 316, annealed |
| Stainless steel 17-4PH | UNS S17400 | 7.80 | 0.282 | 0.780 | MatWeb — AK Steel 17-4 PH, condition H925 |
| Titanium Ti-6Al-4V, Grade 5 | UNS R56400 | 4.43 | 0.160 | 0.443 | MatWeb — Ti-6Al-4V (Grade 5), STA |
| Mould steel P20 | 1.2311 | 7.81 | 0.282 | 0.781 | MatWeb — P20 Premium Modified, hardened 310 HB |
| Hot-work tool steel H13 | 1.2344 | 7.80 | 0.282 | 0.780 | MatWeb — ATI Allegheny Ludlum H13, UNS T20813 |
| Grey cast iron HT250 | EN-GJL-250; ASTM A48 Class 35 | 7.20 | 0.260 | 0.720 | MatWeb — gray cast iron category average (35 grades) |
| Acetal POM (Delrin), unreinforced | — | 1.41 | 0.0509 | 0.141 | Ensinger TECAFORM MT datasheet |
| Nylon PA6, MC | — | 1.14 | 0.0412 | 0.114 | Mitsubishi Chemical Ertalon 6 SA datasheet |
| PEEK, unreinforced | — | 1.31 | 0.0473 | 0.131 | Ensinger TECAPEEK datasheet |
| ABS, general purpose | — | 1.04 | 0.0376 | 0.104 | Ensinger TECARAN ABS datasheet |
| PTFE (Teflon) | — | 2.15 | 0.0777 | 0.215 | Ensinger TECAFLON PTFE datasheet |
| HDPE (PE) | — | 0.95 | 0.0343 | 0.095 | Ensinger TECAFINE HDPE natural product datasheet |
How to read this table. Reference blank for every row: 100 × 100 × 10 mm = 100 cm³, so each blank weight is simply 100 × density and row-to-row differences are pure density differences. Metals carry the lb/in³ value printed by the source; plastics are converted at 1 g/cm³ = 0.036127292 lb/in³.
From Drawing Dimensions to Weight
Four formulas cover almost every quote. Work in mm and g/cm³, and the result is kilograms. The worked example throughout is a Ø50 × 300 mm bar of 6061-T651.
| Shape | Formula | Worked example | Note |
|---|---|---|---|
| Rectangular block | kg = L × W × T × ρ ÷ 1,000,000 | 100 × 100 × 10 mm in 6061: 100 cm³ × 2.70 = 0.270 kg | Use the density row for the exact grade on the order. |
| Round bar | kg = π × D² ÷ 4 × L × ρ ÷ 1,000,000 | Ø50 × 300 mm in 6061: area 1,963.50 mm², volume 589.05 cm³, mass 1.590 kg | At a material price of $X/kg the bar costs 1.590 × $X. |
| Tube / hollow section | kg = π ÷ 4 × (Dₒ² − Dᵢ²) × L × ρ ÷ 1,000,000 | Subtract the bore area before multiplying by length and density | Works for any hollow profile — outer minus inner area. |
| Imperial units | lb = L × W × T × ρ | Dimensions in inches with ρ in lb/in³ from the table above | Stays in inches — no 25.4 conversions needed. |
Compare Cost per Part, Not per Kilogram
The same 100 × 100 × 10 mm blank in four materials. The stainless blank is 2.9× heavier than the aluminium one (7.93 ÷ 2.70) and titanium is 1.6× heavier (4.43 ÷ 2.70). Quoting per kilogram hides that; quoting per part does not.
| Material | Blank weight (kg) | Material cost at $X/kg |
|---|---|---|
| Aluminium 6061 | 0.270 | 0.270 × $X |
| Aluminium 7075 | 0.281 | 0.281 × $X |
| Stainless steel 304 | 0.793 | 0.793 × $X |
| Titanium Ti-6Al-4V | 0.443 | 0.443 × $X |
Finished Weight vs Purchased Weight
The buyer pays for the blank, not for the chips. When a 0.270 kg 6061 blank machines down to a 0.200 kg part, the yield is 74.1% and the 0.070 kg that became swarf has already been paid for.
| Step | Calculation | Result |
|---|---|---|
| Machining yield | 0.200 ÷ 0.270 | 74.1% |
| Material that becomes swarf | 0.270 − 0.200 | 0.070 kg (25.9% of the blank) |
| Cost of the swarf | 0.070 kg × $X/kg | Already invoiced — quote material on the purchased weight and show the yield as a separate line |
When the Density Moves
A density value is only as good as the grade and condition behind it. These are the cases in this table where the number shifts, and what to do on a quote.
| Case | What changes | Action |
|---|---|---|
| P20 mould steel | 7.81 g/cm³ at room temperature → 7.75 hardened to 310 HB; H13 goes 7.81 → 7.78 → 7.67 → 7.53 as it heats toward 400 / 800 °C | Quote with the room-temperature value and state the condition on the quote. |
| POM (Delrin) | unreinforced 1.41 · black 1.42 · PTFE-filled 1.43 · 25% glass-filled 1.54 | State the exact grade — a glass-filled blank is 9% heavier than the plain grade. |
| PEEK | unreinforced 1.31 · 30% glass 1.37 · 50% carbon 1.52 | State the reinforcement — 50% carbon is 16% heavier than virgin PEEK. |
| Nylon PA6 | equilibrium moisture uptake 8% | Long-stored nylon parts weigh more than the dry-state calculation. |
How to Use These Numbers
- The blank-weight column is a common ruler, not a price: every row is 100 cm³ × density, so any figure can be checked in your head and materials can be compared at a glance.
- Subtract what you remove. A 20 mm through hole in the 100 × 100 × 10 mm 6061 blank takes out 8.48 g — 3.14% of the blank — so the part weighs 0.262 kg, not 0.270 kg. In a deep part the removed volume is much larger than the visible hole suggests.
- Never price a part from the finished weight alone. The 25.9% of the blank that becomes chips is invoiced: quote the purchased blank weight and show the machining yield as a separate line.
- Heat treatment changes steel density slightly: P20 drops from 7.81 to 7.75 g/cm³ when hardened to 310 HB, and H13 falls to 7.67 at 400 °C and 7.53 at 800 °C. Quote from the room-temperature value; the actual part will weigh marginally less after heat treatment.
- Reinforced plastics run 5–16% heavier than the unreinforced value (POM 25% glass: 1.54 vs 1.41; PEEK 50% carbon: 1.52 vs 1.31). Quoting the plain grade under-weights the blank — and nylon absorbs up to 8% moisture, so stored parts gain weight.
Frequently Asked Questions
How much does a 100 × 100 × 10 mm 6061 aluminium block weigh?
About 0.270 kg — 100 cm³ × 2.70 g/cm³ = 270 g.
About 0.270 kg — 100 cm³ × 2.70 g/cm³ = 270 g.
How much would the same block weigh in 304 stainless, 316 stainless, and Ti-6Al-4V?
0.793 kg in 304, 0.792 kg in 316, and 0.443 kg in Ti-6Al-4V. The stainless version is about 2.9× heavier than aluminium; titanium about 1.6×.
0.793 kg in 304, 0.792 kg in 316, and 0.443 kg in Ti-6Al-4V. The stainless version is about 2.9× heavier than aluminium; titanium about 1.6×.
How much does a 50 mm diameter × 300 mm long 6061 round bar weigh?
About 1.590 kg (589.05 cm³ × 2.70 g/cm³). At a material price of $X/kg, the bar costs 1.590 × $X.
About 1.590 kg (589.05 cm³ × 2.70 g/cm³). At a material price of $X/kg, the bar costs 1.590 × $X.
Is 6061 lighter or heavier than 7075?
6061 is lighter: 2.70 vs 2.81 g/cm³. The same blank weighs 0.270 kg in 6061 and 0.281 kg in 7075 — 7075 is about 4% heavier.
6061 is lighter: 2.70 vs 2.81 g/cm³. The same blank weighs 0.270 kg in 6061 and 0.281 kg in 7075 — 7075 is about 4% heavier.
How much does a 100 × 100 × 10 mm Delrin (POM) block weigh?
About 0.141 kg — roughly half the same aluminium block and about one sixth of the same 304 stainless block (0.793 kg).
About 0.141 kg — roughly half the same aluminium block and about one sixth of the same 304 stainless block (0.793 kg).
How much material does a 20 mm through hole remove from that 6061 block?
8.48 g — 3.14% of the blank volume. The finished part weighs 0.262 kg, not 0.270 kg.
8.48 g — 3.14% of the blank volume. The finished part weighs 0.262 kg, not 0.270 kg.
Is the material cost of a stainless part always higher than an aluminium one?
Per part, usually yes: the 304 blank weighs 0.793 kg against 0.270 kg for 6061, so at the same $X/kg the material line is about 2.9× larger. Stainless earns its cost by removing corrosion risk, not by weight.
Per part, usually yes: the 304 blank weighs 0.793 kg against 0.270 kg for 6061, so at the same $X/kg the material line is about 2.9× larger. Stainless earns its cost by removing corrosion risk, not by weight.
If the finished part is much lighter than the blank, am I over-paying for material?
No — the blank is what you buy. With a 0.270 kg blank and a 0.200 kg finished part, the machining yield is 74.1% and the remaining 0.070 kg (25.9%) is swarf that was already paid for. Quote the purchased weight and show the yield separately.
No — the blank is what you buy. With a 0.270 kg blank and a 0.200 kg finished part, the machining yield is 74.1% and the remaining 0.070 kg (25.9%) is swarf that was already paid for. Quote the purchased weight and show the yield separately.
Standards & Sources
- MatWeb data pages for aluminium 1060/6061/7075, copper C11000, brass C36000, steels 1045 and 4140, stainless 316 and 17-4PH, titanium Ti-6Al-4V, P20, H13 and the gray cast iron category (35 grades, average 7.20 g/cm³)
- Stainless 304 (7.93 g/cm³ / 0.286 lb/in³): three agreeing sources per ASTM A240/A276, EN 10088-2 (1.4301) and JIS G4304
- Engineering plastics from Ensinger datasheets (TECAFORM MT, TECAPEEK, TECARAN ABS, TECAFLON PTFE, TECAFINE HDPE) and Mitsubishi Chemical Ertalon 6 SA; plastics lb/in³ converted at 1 g/cm³ = 0.036127292 lb/in³
- Cross-checks: ASM Handbook Vol. 2 (1990), EN 10088-1 (austenitic group 7.9 g/cm³), ASTM A240/A276/A479, JIS G4304/G4305
- Grey cast iron HT250 uses the MatWeb category average (7.20 g/cm³; the 35-grade range is 6.80–7.34) — quote on the average, flag the range if the casting is critical
Related Pages
- /wiki/reference/thermal-expansion-coefficients/ — Sibling quick table: thermal expansion for the same materials
- /wiki/materials/aluminum/ — Aluminum alloys in detail: grades, tempers and machining behaviour
- /wiki/materials/plastics/ — Engineering plastics for CNC machining, including filled grades
- /resources/dfm-guide/ — DFM checklist to run against a drawing before quoting