SizingKitAlloy, not just aluminum
Aluminum weight calculator
Weight per foot and per piece for aluminum bar, plate, tube and angle, computed in all five wrought alloys at once so the 4.85% between 5052 and 7075 is visible rather than averaged away. Free, no signup. It then answers the question that actually brought you: what the part weighs if it replaces a steel one — a third of it on the same drawing, and rather more than that once the section grows to match the stiffness.
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- No signup
- 5 alloys side by side
- Temper-independent
- 4 steel comparisons
One section, and the alloy you are pricing it in
The form 5052, 2024 and 7075 are usually bought in. Cast tooling plate is a different product again — it is machined flat and is not the same alloy as rolled plate of a similar number.
No temper appears in this list on purpose: T6, T651, H32 and O are the same density. Heat treatment and cold work move strength, not mass.
Section dimensions are inches unless you write a unit; the length is feet unless you write one. Fractions read everywhere — 1/2, 1 1/4.
ALUMINUM 6061
PER FOOT
2.341 lb
3.4839 kg/m
THE PIECE
28.09 lb
12.743 kg
Density 0.09754 lb/in³. Aluminum Association alloy 6061: 2.70 g/cm³ (0.0975 lb/in³) — the figure the Aluminum Design Manual uses for 6061 extrusion weights. Same in T6, T651 and O — heat treatment moves strength, not density. 6063 extrusion sits with it at 2.70.
The same section in all five alloys, and in steel
A 4.85% spread from the lightest wrought alloy to the heaviest, which is small next to the 65.6% between any of them and carbon steel — and large enough to be visible on a truckload.
| Alloy | g/cm³ | lb/in³ | vs 6061 | lb/ft | kg/m |
|---|---|---|---|---|---|
| Aluminum 5052 | 2.68 | 0.09682 | -0.74% | 2.3237 | 3.4581 |
| Aluminum 6061 | 2.70 | 0.09754 | 0% | 2.341 | 3.4839 |
| Aluminum 1100 (commercially pure) | 2.71 | 0.0979 | 0.37% | 2.3497 | 3.4968 |
| Aluminum 2024 | 2.78 | 0.10043 | 2.96% | 2.4104 | 3.5871 |
| Aluminum 7075 | 2.81 | 0.10152 | 4.07% | 2.4364 | 3.6258 |
| Carbon steel — for scale | 7.85 | 0.2836 | +191% | 6.8064 | 10.129 |
Published nominal densities of the named alloys, from the ASTM and Aluminum Association specifications cited row by row. Stored as g/cm³ × 1000; lb/in³ and lb/ft³ are converted at the exact definitions of the pound and the inch (1 lb/in³ = 27,679.9047 kg/m³), not transcribed separately.
Replacing a steel part with Aluminum 6061
Against A36 hot-rolled structural steel, and each row asks a different question of the substitution. Only the first one keeps the drawing.
| Matched on | What the section becomes | Weight vs steel | Saving |
|---|---|---|---|
| Same section, part for partThe comparison everybody quotes, and the one nobody builds: it holds only where the part was never working near a limit in the first place — a cover, a bracket, a spacer. | Identical dimensions | 34.4% | 65.6% |
| Same tensile loadAt the ultimate tensile strengths this site carries: 45,000 psi for Aluminum 6061-T6 against 58,000 psi for Structural steel, hot-rolled (A36). A real design works from yield with a factor on it, not from ultimate. | Area × 1.289 | 44.3% | 55.7% |
| Same bending stiffnessAluminum is a third as stiff as steel — 10 against 29 million psi — and stiffness in bending goes as the cube of the thickness, so matching it costs 43% more thickness whatever the alloy. | Thickness × 1.426, same width | 49% | 51% |
| Same bending strengthSection modulus goes as the square of the thickness, so this one costs less section than stiffness does. It is also the case that fails soonest in fatigue — aluminum has no endurance limit, and a steel part that ran forever at a stress may not have an aluminum equivalent that does. | Thickness × 1.135, same width | 39% | 61% |
Published Young's moduli: 29,000 ksi for structural steel as specified by the AISC Steel Construction Manual, 10,000 ksi for aluminum as specified by the Aluminum Design Manual, and standard published values for the remaining metals. The GPa column is converted at 1 MPa = 145.0377 psi. Strength rows: Typical ultimate tensile strengths from the governing product specifications named row by row — ASTM A36 for hot-rolled structural steel, ASTM A240 for stainless sheet, ASTM B209 for aluminum sheet. The tonnage factor is simply the tensile strength divided by the 60,000 psi the air-bending chart assumes.
Stiffness does not come with the alloy. 10,000 ksi / 69 GPa, the value the Aluminum Design Manual uses. Almost exactly one third of steel, and near enough identical across the wrought alloys — 7075 is no stiffer than 6061, only stronger. An aluminum beam of the same section deflects three times as far as a steel one. That is the sentence to keep in mind before specifying 7075 to stop something flexing: it is more than twice the strength of 6061 and exactly as stiff, so a part that is bending too far needs a different section, not a stronger alloy. If the part is a beam, the spring rate calculator shows the same relation for a coil spring — rate follows the shear modulus and the geometry, never the temper.
What varies, and what does not. None of these is a defined value. A density is a measured property of a commercial alloy, so treat every figure as a default you may override — the per-row 'varies' note says by how much and what moves it. Cast alloys carry porosity and weigh under the calculated figure; gray iron moves ±4% with its class. And the delivered weight of mill product differs from the calculated weight for a separate reason — see MILL_WEIGHT_TOLERANCE. For the aluminum rows in particular the spread within an alloy is small and the spread between alloys is not: the figures above are separated because averaging the five into one “aluminum” density would land 2.7% under on 7075 and 2.1% over on 5052, on every order written against it. These are reference tables and arithmetic — a load-bearing substitution from steel to aluminum is a design change, and it is signed by a qualified engineer rather than justified by a weight ratio.
How to price aluminum stock without averaging the alloys
The alloy is the input that matters here. The temper is not, and that surprises people.
Enter the section once — every alloy is computed from it
Round rod, square rod, plate and flat bar, round, square and rectangular tube, and extruded angle. Tube takes outside dimension and wall, the way it is drawn and the way it is sold. One section produces the whole column of alloys, because the comparison is the point of the page rather than a feature bolted onto it.
Pick the alloy, and ignore the temper entirely for weight
6061-T6, 6061-T651 and 6061-O have exactly the same density: heat treatment and cold work rearrange the microstructure and move strength, hardness and formability without adding or removing atoms. That is why the picker lists 6061 rather than 6061-T6. The temper matters enormously everywhere else in the job — it decides whether the material will bend without cracking, and what it will hold once it has.
Read the substitution table on the row that matches your part
Same section is the 65.6% saving everyone quotes, and it applies only where the steel part was never near a limit. If the part has to be as stiff, the thickness grows 42.6% and the saving falls to 51%. If it has to be as strong in bending, 6061-T6 needs 13.5% more thickness and saves 61%. Every row states what the section becomes, so you can see what is actually being proposed rather than a percentage.
Technical specifications
| Alloys carried | Five, separately: 1100 at 2.71 g/cm³, 2024 at 2.78, 5052 at 2.68, 6061 at 2.70 and 7075 at 2.81. Each carries the Aluminum Association composition it comes from and what moves it. |
|---|---|
| Spread across the family | 4.85% from 5052 to 7075. Against 6061 as the reference: 5052 is 0.74% lighter, 1100 is 0.37% heavier, 2024 is 2.96% and 7075 is 4.07%. Zinc, at two and a half times the density of aluminum, is what makes 7075 the heavy one. |
| Effect of temper | None. T3, T4, T6, T651, H32 and O all share their alloy's density, which is why no temper appears in the picker. It is the only input on this page that changes nothing at all. |
| Against carbon steel | 6061 is 34.4% of the weight of steel at the same section — a 65.6% saving. Matching bending stiffness costs 42.6% more thickness and drops that to 51.0%; matching bending strength in 6061-T6 costs 13.5% more thickness and drops it to 61.0%. |
| Stiffness figures | 10,000 ksi for the wrought aluminum alloys per the Aluminum Design Manual, 29,000 ksi for structural steel per the AISC manual. Aluminum's modulus does not move with alloy: 7075 is more than twice the strength of 6061 and precisely as stiff. |
| Strength figures | Ultimate tensile from the bending table this site carries: 45,000 psi for 6061-T6 and 33,000 psi for 5052-H32 against 58,000 psi for A36 steel. There is no row for 1100, 2024 or 7075, so those strength comparisons stay blank rather than being invented. |
| Worked example | A 4 × 1/2 in bar, 12 ft long: 27.88 lb in 5052, 28.09 in 6061, 29.24 in 7075 and 81.68 lb in carbon steel. The alloy choice moves it by 1.4 lb; the decision to use aluminum at all moves it by 54. |
| Where it runs | In this browser tab, with nothing uploaded and no alloy list fetched from anywhere. |
Frequently asked questions
Does T6 weigh more than T651 or annealed 6061?
No — every temper of an alloy has the same density, and this is the most common misconception on the subject. Tempering, solution heat treating, artificial aging and stress-relief stretching all rearrange how the alloying elements sit in the aluminum lattice; none of them changes how many atoms are in a cubic inch by anything measurable. What the temper decides is strength, ductility and how tight a radius the material will take without cracking — 6061-T6 is roughly three times the yield strength of 6061-O and identical on a scale.
Why is 7075 heavier than 6061 if it is the high-performance alloy?
Because performance in aluminum is bought with zinc and copper, and both are much denser than aluminum. 7075 is nominally 5.6% zinc, 2.5% magnesium and 1.6% copper; zinc is 2.6 times the density of aluminum and copper 3.3 times, so the alloy comes out at 2.81 g/cm³ against 6061's 2.70 — 4.07% heavier. 2024, at 4.4% copper, lands in between at 2.78. The 5000 series runs the other way for the same reason: magnesium is lighter than aluminum, which is what makes 5052 the lightest structural wrought alloy at 2.68.
Is aluminum really a third of the weight of steel?
At the same section, yes: 6061 is 34.4% of carbon steel, so an identical part is 65.6% lighter. The trouble is that identical parts are rare. Aluminum's modulus is 10,000 ksi against steel's 29,000, so a beam of the same section deflects nearly three times as far, and matching the stiffness means growing the thickness by 42.6% — after which the saving is 51%, not 66%. Matching bending strength in 6061-T6 needs 13.5% more thickness and lands at 61%. Every real substitution sits somewhere in that band, and which end depends on whether the part was limited by stiffness, strength or neither.
Can I use a single 'aluminum' density of 0.098 lb/in³?
For a rough figure yes, and for a purchase order or a shipping weight no. Averaging the five alloys gives about 2.74 g/cm³, which is 2.7% under on 7075 and 2.1% over on 5052 — on a tonne of material that is a range of 47 kg, which is well outside anybody's rounding and visible on the invoice. The single figure also hides which way the error goes: the two alloys people most often use for high-value machined parts, 2024 and 7075, are both on the heavy side of the average, so a fabricator quoting bar stock from the middle of the family is systematically under-buying.
Where does the extruded shape stop matching the calculation?
At every corner and every fillet, and in aluminum that is more of the section than in steel. Extruded square and rectangular tube has radiused corners inside and out, so the sharp-cornered area used here runs over the real one — most on small sections with a heavy wall, where the corner radius is a large share of the profile. Extruded angle carries a filleted heel and a taper on the legs in some dies. And an extrusion is not a rolled shape at all: for a structural aluminum profile with a published weight per foot, the extruder's own figure includes all of that and this one does not.
Does anodizing add weight?
Almost nothing, and it comes partly out of the metal rather than being added to it. Anodizing converts the surface of the aluminum into aluminum oxide rather than plating something on: roughly half the coating thickness grows outward and half consumes base metal, so a Type II coating of a few ten-thousandths of an inch changes the dimensions more than it changes the weight. Type III hard coat is thicker and the same logic applies. Paint and powder coat do add mass, but as a coating weight per square foot that belongs to the finisher's data rather than to the density of the alloy.
Why is the strength comparison blank for 2024 and 7075?
Because the tensile strengths this site carries stop at 6061-T6 and 5052-H32, and a page that reaches past its own table is exactly what this site exists not to be. The figures would have to come from ASTM B209, where they are specified as minimums that vary by product form and by thickness band, and for the 2000 and 7000 series they also move further with temper than for any other alloy here — 2024-T3, T4 and T851 are three different materials sharing a number. Take the minimum for your form and thickness from B209 or from the mill certificate, and the arithmetic in the table above is two lines on paper.
About the five alloys, and the substitution that is never like-for-like
Aluminum is the only material in this section where the alloy is a bigger question than the shape. Steel is steel to within half a percent across the whole carbon and low-alloy family, so a single density serves; the wrought aluminum alloys span 4.85%, and the spread is not random. Everything useful added to aluminum except magnesium is denser than aluminum, so the alloys sort themselves by what they were alloyed for: 5052, whose 2.5% magnesium is lighter than what it replaces, at 2.68 g/cm³; commercially pure 1100 at 2.71; 6061 at 2.70; 2024, with 4.4% copper, at 2.78; and 7075, with 5.6% zinc, at 2.81. The temper suffix that follows all of them on a drawing does nothing to any of this. T6, T651, H32 and O are heat treatments and work histories, and they move strength by a factor of three while leaving mass exactly where it was.
Which brings up the reason most people open this page, which is not aluminum at all but steel. “A third of the weight” is a true statement about identical sections and a misleading one about real parts, because the part is usually being asked to do the same job rather than be the same shape. Stiffness is where it bites hardest: aluminum's modulus is 10,000 ksi against steel's 29,000 and — this is the part that catches people — it does not move with the alloy at all. 7075 is more than twice the strength of 6061 and exactly as stiff, so a part that flexes too much cannot be fixed by specifying a better alloy, only by growing the section. Because bending stiffness goes as the cube of thickness, matching steel costs 42.6% more thickness and the 65.6% saving becomes 51%. Bending strength is cheaper, at the square rather than the cube: 6061-T6 needs 13.5% more thickness and keeps 61%. And there is one thing no section change buys back — aluminum has no fatigue endurance limit, so a steel part that survived indefinitely at a working stress has no aluminum equivalent that does.
Three neighbors pick up where this page stops. Where the material is sold as a sheet rather than a length, the plate weight calculator nests the blanks and prices the drop, and it fixes the alloy at 5052 for exactly the reason this page splits them out — on a sheet job the drop moves the number more than the alloy does. Where the metal is stainless, the stainless steel weight calculator has the same argument about grades, with a bigger gap in it. And where aluminum is being bent rather than bought, the press brake tonnage calculator wants the tensile strength that changed with the temper this page ignores — 5052-H32 and 6061-T6 take noticeably different tonnage, and 6061-T6 has a minimum bend radius that will crack the part if the die is wrong. A structural substitution from steel to aluminum is a design change with a qualified engineer at the end of it, not a weight ratio.
Where these alloy figures are worked out
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — loads, lengths, nameplate ratings, the rates your utility charges you — is uploaded, logged or kept, which is also why the calculators carry on working in a mechanical room with no signal.