Common Units for Aluminum Density
| Unit | Approximate value for pure aluminum | Use |
|---|---|---|
| g/cm³ | 2.70 | Laboratory and material-property tables |
| kg/m³ | 2,700 | Metric volume and engineering calculations |
| lb/in³ | 0.0975 | Imperial part-volume calculations |
| lb/ft³ | 168.5 | Large-volume and freight estimates |
Why Alloy Density Is Not Exactly the Same
Alloying elements change mass per unit volume. Values for 2xxx, 5xxx, 6xxx and 7xxx alloys can differ enough to matter in large structures or precision mass calculations. Temper normally changes mechanical properties much more than density, but the material specification and trusted alloy data should still be used.
Weight Formulas for Common Product Forms
| Form | Volume formula | Weight calculation |
|---|---|---|
| Sheet / plate | length × width × thickness | volume × density |
| Round bar | π × diameter² / 4 × length | volume × density |
| Round tube | π × (OD² − ID²) / 4 × length | volume × density |
| Rectangular bar | width × thickness × length | volume × density |
Keep all dimensions in a consistent unit system. For tube, calculate ID from OD and twice the wall thickness only when the nominal dimensions and tolerances support that assumption. Actual shipment weight also includes cut-length variation, tolerances, packaging and quantity.
Worked Metric Example
For a 1,000 mm × 500 mm × 10 mm plate, volume is 5,000,000 mm³, or 0.005 m³. Using 2,700 kg/m³ gives an estimated mass of 13.5 kg. This is a nominal estimate; the actual alloy density and thickness tolerance change the result.
Common Calculation Errors
- Mixing millimetres and metres without conversion
- Using 2.70 as kg/cm³ instead of g/cm³
- Using solid-bar volume for a tube
- Ignoring alloy-specific density in precision designs
- Treating nominal dimensions as measured shipment dimensions
Information Needed for a Weight Quote
- Alloy and temper
- Product form and dimensions
- Dimension basis and tolerances
- Cut length and quantity
- Whether theoretical or actual weight controls commercial terms
Send alloy, dimensions, tolerance and quantity for a product-specific weight and RFQ review.
Post time: Jul-15-2025