6061 Aluminum Density: Values, Unit Conversions, and Fabrication Implications

Source: Aluminum Association, Aluminum Standards and Data; ASM Handbook, Vol. 1,

And source, please refer to the Metal Density Chart.

These values apply to all 6061 tempers — O, T4, T451, T6, T651, and T6511. I’ll explain why temperature does not affect density in a dedicated section below, because it’s a question I field regularly, and most references leave it unanswered.

Why 6061 Aluminum Density Equals Pure Aluminum Density

This is the part that surprises most people who work with 6061. You add alloying elements to it. Shouldn’t that change the density?

The short answer: it does, but the effect is so small it rounds away.

6061’s composition — and what each element contributes

Per ASTM B209, the chemical composition of 6061 aluminum is:

Now look at the two principal alloying elements — magnesium and silicon. Both are less dense than aluminum. Magnesium at 1,738 kg/m³ is 36% lighter than aluminum; silicon at 2,330 kg/m³ is 14% lighter. When you dissolve them into the aluminum matrix, they slightly lower the density.

The trace additions of copper (8,960 kg/m³) and chromium (7,190 kg/m³) push it back up. These effects nearly cancel at the concentrations permitted by ASTM B209. The net result, verified by measurement, is a density indistinguishable from pure aluminum: 2,700 kg/m³.

This is what makes 6061 practical for weight-critical applications — you gain substantial strength and corrosion resistance through alloying, and you pay nothing in density penalty for it.

How 6061 compares to other common aluminum alloys

Not every aluminum alloy works this cleanly. When alloying elements are dense and present in larger amounts, the density shifts meaningfully:

The practical conclusion: if your design could use either 6061 or 7075, the 7075 part weighs about 4% more for the same geometry. That difference is real and compounds on larger assemblies — but it rarely drives alloy selection on its own. Strength and heat treat response do.

6061 Aluminum Density Across All Tempers — Why T6 and T4 Weigh the Same

I want to address this directly because it’s a source of genuine confusion in our quoting process.

When a customer asks me to quote the same 6061 part in T4 and T6, I use the same density for both. The weight formula does not change between tempers. Here’s the data that proves it:

Source: Aluminum Association, Aluminum Standards and Data.

Density is mass per unit volume. Temper changes the microstructure — specifically, the size and distribution of Mg₂Si precipitates that form during heat treatment and age hardening — but it does not add or remove atoms from the lattice. The total mass per cubic meter stays constant. Yield strength jumps by a factor of five from O to T6. The weight formula doesn’t care.

I’ve reviewed drawings from engineers who attached different densities to T4 and T6 callouts because they assumed a harder material must be denser. It isn’t. One density value covers all temperatures of 6061: 2,700 kg/m³.

6061 Aluminum Density in kg/m³: The SI Reference for Engineering Calculations

The standard engineering density of 6061 aluminum in SI units is 2,700 kg/m³.

This is the number you use in:

• Finite element analysis (FEA) — material property input
• Shipping manifest weight calculations
• Structural load calculations for elevated or suspended assemblies
• Nesting sheet weight for pallet and freight planning

Weight formula in SI units:

Weight (kg) = Length (m) × Width (m) × Thickness (m) × 2,700

Worked example — a full 6061-T6 sheet, standard 1,220 mm × 2,440 mm × 6 mm:

Weight = 1.220 × 2.440 × 0.006 × 2,700 = 48.3 kg

We run this calculation every time we load a sheet on the laser table. A standard pallet of twenty 6 mm 6061 sheets — a common order size for structural bracket work — weighs approximately 966 kg. That’s the number that goes on the shipping document and determines the forklift class we use to move it.

6061 Aluminum Density in g/cm³: The Laboratory Reference Value

The density of 6061 aluminum in g/cm³ is 2.70 g/cm³.

This is numerically identical to the density expressed in g/mL, because 1 mL = 1 cm³ by definition. Both values appear in technical datasheets and materials handbooks, and both mean the same thing.

The g/cm³ unit appears most often in:

• Material specification datasheets
• Laboratory verification of material identity
• Metallurgical and materials science literature
• Procurement specifications for aerospace and defense work

One unit of confusion worth clarifying: Some engineers use specific gravity in place of g/cm³. The specific gravity of 6061 aluminum is also 2.70 — dimensionless, equal to the ratio of 6061’s density to water’s density (1.0 g/cm³ = 1,000 kg/m³). The numbers look identical; the units are different. In calculations, they are not interchangeable without checking dimensional consistency.

6061 Aluminum Density in lb/in³: The Value for North American Fabricators

The density of 6061 aluminum in lb/in³ is 0.0975 lb/in³.

Weight formula in imperial units:

Weight (lb) = Length (in) × Width (in) × Thickness (in) × 0.0975

Worked example — a 6061-T6 bracket, 12 in × 8 in × 0.25 in:

Weight = 12 × 8 × 0.25 × 0.0975 = 2.34 lb

A note on the value you may see elsewhere: many quick-reference tables and even some supplier datasheets list 0.1 lb/in³ for aluminum. The precise conversion from 2,700 kg/m³ is 0.09752 lb/in³, which rounds to 0.0975 — not 0.1. The difference is 2.5%. On a small part or a single shipment, it doesn’t matter. On a high-volume production contract with hundreds of parts per pallet and tight freight class margins, using 0.1 consistently overestimates weight and costs money. Use 0.0975 for every calculation that requires more than two significant figures.

6061 Aluminum Density in Fabrication: What It Means When You’re Actually Cutting the Material

This is where most density articles stop contributing useful information. The value is 2,700 kg/m³. You’ve seen it. But density shows up in the fabrication environment in ways that aren’t obvious until you’ve run enough jobs to notice.

Nesting efficiency and sheet weight on the laser table

6061 is the most common aluminum alloy we laser-cut. Our fiber laser tables hold a standard 1,220 × 2,440 mm sheet in gauges from 0.8 mm to 25 mm. Every job brief includes the sheet weight, because it determines:

• Whether a single operator can handle the sheet manually, or whether we need a sheet lifter
• How many sheets can we stack per pallet before we hit our freight class threshold
• What the remnant offcut weighs, which matters for scrap valuation on tight-margin jobs

The weight calculation is always the same formula. What changes is the gauge — and the result surprises customers who’ve only worked with steel. A 3 mm 6061 sheet at full size weighs 24.1 kg. A 3 mm A36 steel sheet of the same size weighs 70.0 kg. The laser table holds the same footprint either way, but our material handling process is completely different. We treat aluminum sheets like paper compared to steel. The density difference — 2,700 vs. 7,850 kg/m³ — is felt physically every day.

Thermal expansion during cutting: why density isn’t the only physical property that matters

Aluminum’s density is low. Its coefficient of thermal expansion is high — approximately 23.6 μm/(m·°C), nearly twice that of steel. During laser cutting of 6061, a 300 mm dimension can grow by up to 0.57 mm if the material heats to 100°C above ambient. We account for this on tight-tolerance parts by allowing sufficient cooling time between cuts on the same sheet and by processing thin gauges with slower, lower-heat cutting parameters.

The density value itself doesn’t change during cutting — the bulk material temperature stays close to ambient on most of the sheet. But understanding the full physical profile of 6061 (low density, high thermal expansion, moderate thermal conductivity at approximately 167 W/m·K) is what lets you quote it accurately and cut it cleanly.

Part weight estimation in multi-material assemblies

We regularly quote assemblies where some components are 6061, and others are 304 stainless or mild steel. Using the correct density for each material is non-negotiable for accurate assembly weight, which the customer needs for packaging, mounting hardware, and structural clearance certification.

6061 component: 2,700 kg/m³ 304 stainless component: 7,930 kg/m³ A36 steel component: 7,850 kg/m³

A mixed assembly estimated with the wrong density for the aluminum components can come out 20–30% off in total weight if the aluminum parts are large. I’ve reviewed BOMs from engineering teams that had used 7,850 for every material — the aluminum parts were treated as if they were steel. The quoted assembly weight was more than double what the customer received.

6061 Aluminum Density and Its International Equivalents

6061 is an American Aluminum Association designation. When you work with European or Asian supply chains, the same alloy appears under different names — but the density is always 2,700 kg/m³.

Source: Michael Smith Engineers Grade Comparison Table (DIN/BS/USA/Japan).

EN AW-6082 is not identical to 6061. This is the most important distinction for international procurement. European structural aluminum drawings frequently specify 6082 rather than 6061 because 6082 is the preferred structural extrusion grade in Europe. It has a slightly different composition — higher in silicon and manganese, lower in copper — and a modestly higher typical tensile strength. The density is the same: 2,700 kg/m³. If a European drawing arrives specifying EN AW-6082 for a laser-cut plate component and you’re sourcing from North American stock, 6061-T6 is the closest practical substitute. Confirm with the design engineer if the application has tight mechanical property requirements.

Frequently Asked Questions About 6061 Aluminum Density

Q: What is the density of 6061 aluminum in kg/m³? 2,700 kg/m³. This is the Aluminum Association standardized value, consistent across all 6061 tempers (O, T4, T6, T651).

Q: What is the density of 6061-T6 aluminum specifically? 2,700 kg/m³ — identical to 6061-O, T4, and all other tempers. Temper affects mechanical properties, not mass per unit volume. A 6061-T6 part and an identical 6061-O part weigh the same.

Q: Is the density of 6061 different from pure aluminum? Effectively no. Pure aluminum has a density of 2,699 kg/m³; 6061 is 2,700 kg/m³. The principal alloying elements in 6061 — magnesium (less dense than aluminum) and silicon (also less dense) — partially cancel the contribution of trace copper and chromium (both denser than aluminum). The net effect rounds to zero at any practical level of precision.

Q: How does 6061 density compare to 7075? 7075 aluminum has a density of 2,810 kg/m³, approximately 4.1% higher than 6061’s 2,700 kg/m³. The difference comes from 7075’s zinc content (5.1–6.1%), which has a density of 7,133 kg/m³. For a part where every gram matters — aerospace brackets, drone frames — the 7075 part will be about 4% heavier for the same geometry. 7075 also delivers roughly 85% higher tensile strength (572 MPa vs. 310 MPa for T6), so the weight-per-unit-strength comparison still favors both alloys depending on the specific loading condition.

Q: What is the weight of a standard 6061 aluminum sheet? Depends on gauge and size. For a standard 1,220 × 2,440 mm sheet:

• 1.6 mm (1/16 in): 12.9 kg
• 3.2 mm (1/8 in): 25.8 kg
• 6.4 mm (1/4 in): 51.5 kg
• 12.7 mm (1/2 in): 102.2 kg

Formula: Weight (kg) = 1.220 × 2.440 × thickness (m) × 2,700

Q: What is the density of 6061 aluminum in lb/in³? 0.0975 lb/in³. Not 0.1 — that’s a rounded approximation. The exact conversion from 2,700 kg/m³ is 0.09752 lb/in³.

Q: Can I use 6061 density for 6063? Yes. 6063 shares the same principal alloying elements (Mg + Si) in similar proportions and has an identical density of 2,700 kg/m³. The two alloys differ in composition ranges and mechanical properties — 6063 is softer and better suited to extrusion and architectural applications — but the weight calculation is the same.

References

1. ASTM B209, Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate, ASTM International, current edition. (Chemical composition of 6061 per Table 1; mechanical property requirements per Table 3.)
2. Aluminum Association, Aluminum Standards and Data, current edition. (Density values by alloy and temper; composition limits; mechanical property minima and typical values.)
3. ASM Handbook, Volume 1: Properties and Selection — Irons, Steels, and High-Performance Alloys, 10th Edition. ASM International, 1990. (Physical properties of wrought aluminum alloys; density and thermal expansion data.)
4. Michael Smith Engineers Limited, Material Grade Comparison Table (DIN/BS/USA/Japan cross-reference), available at michaelsmithengineers.co.uk. (EN AW-6061 and EN AW-6082 designations and US equivalency; international grade mapping.)

Density of Aluminum: The Complete Reference Guide