Aluminum 6061-T6 Flat Bar Weight
Mass per metre and per foot for aluminum 6061-t6 flat bar at 2,700 kg/m³ (ASTM B221 / B209 (T6 temper)). Every figure is for the section as drawn. A 6 m length of this size weighs 4.9 kg (10.9 lb per 20 ft).
At the reference dimensions (w = 50 mm, t = 6 mm) this section has a cross-sectional area of 300.0 mm², giving 0.810 kg/m (0.544 lb/ft). Against carbon steel's 7,850 kg/m³ that is -65.6 % — the same section in steel would be 2.355 kg/m.
Flat Bar — formula and derivation
Area of a flat bar
A = w · t
A = w × t, where w is width and t is thickness
Worked through with the default dimensions:
A = w × tA = 50 × 6A = 300.0 mm²
- w
- Width
- t
- Thickness
Weight follows from the area with no further geometry: m = A × 10⁻⁶ × ρ, where A is in mm², ρ in kg/m³ and m in kg/m. At 2,700 kg/m³ that is 0.8100 kg/m for the reference size above.
AL 6061 flat bar — size series
| Width | 3.0 | 4.0 | 5.0 | 6.0 | 8.0 | 10 | 12 | 16 | 20 |
|---|---|---|---|---|---|---|---|---|---|
| 12 mm | 0.097 kg/m · 0.065 lb/ft | 0.130 kg/m · 0.087 lb/ft | 0.162 kg/m · 0.109 lb/ft | 0.194 kg/m · 0.131 lb/ft | 0.259 kg/m · 0.174 lb/ft | 0.324 kg/m · 0.218 lb/ft | 0.389 kg/m · 0.261 lb/ft | 0.518 kg/m · 0.348 lb/ft | 0.648 kg/m · 0.435 lb/ft |
| 16 mm | 0.130 kg/m · 0.087 lb/ft | 0.173 kg/m · 0.116 lb/ft | 0.216 kg/m · 0.145 lb/ft | 0.259 kg/m · 0.174 lb/ft | 0.346 kg/m · 0.232 lb/ft | 0.432 kg/m · 0.290 lb/ft | 0.518 kg/m · 0.348 lb/ft | 0.691 kg/m · 0.464 lb/ft | 0.864 kg/m · 0.581 lb/ft |
| 20 mm | 0.162 kg/m · 0.109 lb/ft | 0.216 kg/m · 0.145 lb/ft | 0.270 kg/m · 0.181 lb/ft | 0.324 kg/m · 0.218 lb/ft | 0.432 kg/m · 0.290 lb/ft | 0.540 kg/m · 0.363 lb/ft | 0.648 kg/m · 0.435 lb/ft | 0.864 kg/m · 0.581 lb/ft | 1.080 kg/m · 0.726 lb/ft |
| 25 mm | 0.202 kg/m · 0.136 lb/ft | 0.270 kg/m · 0.181 lb/ft | 0.338 kg/m · 0.227 lb/ft | 0.405 kg/m · 0.272 lb/ft | 0.540 kg/m · 0.363 lb/ft | 0.675 kg/m · 0.454 lb/ft | 0.810 kg/m · 0.544 lb/ft | 1.080 kg/m · 0.726 lb/ft | 1.350 kg/m · 0.907 lb/ft |
| 30 mm | 0.243 kg/m · 0.163 lb/ft | 0.324 kg/m · 0.218 lb/ft | 0.405 kg/m · 0.272 lb/ft | 0.486 kg/m · 0.327 lb/ft | 0.648 kg/m · 0.435 lb/ft | 0.810 kg/m · 0.544 lb/ft | 0.972 kg/m · 0.653 lb/ft | 1.296 kg/m · 0.871 lb/ft | 1.620 kg/m · 1.089 lb/ft |
| 40 mm | 0.324 kg/m · 0.218 lb/ft | 0.432 kg/m · 0.290 lb/ft | 0.540 kg/m · 0.363 lb/ft | 0.648 kg/m · 0.435 lb/ft | 0.864 kg/m · 0.581 lb/ft | 1.080 kg/m · 0.726 lb/ft | 1.296 kg/m · 0.871 lb/ft | 1.728 kg/m · 1.161 lb/ft | 2.160 kg/m · 1.451 lb/ft |
| 50 mm | 0.405 kg/m · 0.272 lb/ft | 0.540 kg/m · 0.363 lb/ft | 0.675 kg/m · 0.454 lb/ft | 0.810 kg/m · 0.544 lb/ft | 1.080 kg/m · 0.726 lb/ft | 1.350 kg/m · 0.907 lb/ft | 1.620 kg/m · 1.089 lb/ft | 2.160 kg/m · 1.451 lb/ft | 2.700 kg/m · 1.814 lb/ft |
| 60 mm | 0.486 kg/m · 0.327 lb/ft | 0.648 kg/m · 0.435 lb/ft | 0.810 kg/m · 0.544 lb/ft | 0.972 kg/m · 0.653 lb/ft | 1.296 kg/m · 0.871 lb/ft | 1.620 kg/m · 1.089 lb/ft | 1.944 kg/m · 1.306 lb/ft | 2.592 kg/m · 1.742 lb/ft | 3.240 kg/m · 2.177 lb/ft |
| 80 mm | 0.648 kg/m · 0.435 lb/ft | 0.864 kg/m · 0.581 lb/ft | 1.080 kg/m · 0.726 lb/ft | 1.296 kg/m · 0.871 lb/ft | 1.728 kg/m · 1.161 lb/ft | 2.160 kg/m · 1.451 lb/ft | 2.592 kg/m · 1.742 lb/ft | 3.456 kg/m · 2.322 lb/ft | 4.320 kg/m · 2.903 lb/ft |
| 100 mm | 0.810 kg/m · 0.544 lb/ft | 1.080 kg/m · 0.726 lb/ft | 1.350 kg/m · 0.907 lb/ft | 1.620 kg/m · 1.089 lb/ft | 2.160 kg/m · 1.451 lb/ft | 2.700 kg/m · 1.814 lb/ft | 3.240 kg/m · 2.177 lb/ft | 4.320 kg/m · 2.903 lb/ft | 5.400 kg/m · 3.629 lb/ft |
Rows: width (mm). Columns: thickness (mm). Computed for Aluminum 6061-T6 at 2700 kg/m³.
| Width | 3.0 | 4.0 | 5.0 | 6.0 | 8.0 | 10 | 12 | 16 | 20 |
|---|---|---|---|---|---|---|---|---|---|
| 12 mm | 36.0 | 48.0 | 60.0 | 72.0 | 96.0 | 120.0 | 144.0 | 192.0 | 240.0 |
| 16 mm | 48.0 | 64.0 | 80.0 | 96.0 | 128.0 | 160.0 | 192.0 | 256.0 | 320.0 |
| 20 mm | 60.0 | 80.0 | 100.0 | 120.0 | 160.0 | 200.0 | 240.0 | 320.0 | 400.0 |
| 25 mm | 75.0 | 100.0 | 125.0 | 150.0 | 200.0 | 250.0 | 300.0 | 400.0 | 500.0 |
| 30 mm | 90.0 | 120.0 | 150.0 | 180.0 | 240.0 | 300.0 | 360.0 | 480.0 | 600.0 |
| 40 mm | 120.0 | 160.0 | 200.0 | 240.0 | 320.0 | 400.0 | 480.0 | 640.0 | 800.0 |
| 50 mm | 150.0 | 200.0 | 250.0 | 300.0 | 400.0 | 500.0 | 600.0 | 800.0 | 1,000.0 |
| 60 mm | 180.0 | 240.0 | 300.0 | 360.0 | 480.0 | 600.0 | 720.0 | 960.0 | 1,200.0 |
| 80 mm | 240.0 | 320.0 | 400.0 | 480.0 | 640.0 | 800.0 | 960.0 | 1,280.0 | 1,600.0 |
| 100 mm | 300.0 | 400.0 | 500.0 | 600.0 | 800.0 | 1,000.0 | 1,200.0 | 1,600.0 | 2,000.0 |
Area is a property of the geometry alone, so this table is the same for every material. It is what you enter into a stress calculation; the mass table is what you enter into an order.
Each row is one nominal size. Because the area is computed from your dimensions rather than read from a mill table, a non-standard size is just as accurate — put it into the calculator above rather than interpolating between rows.
The same flat bar in every material
Geometry is fixed and only density changes, so this table is the whole material-selection question in one view. Aluminum 6061-T6 is highlighted. The percentage column is against carbon steel, which is the figure most quotations are built on.
| Material | Density kg/m³ | lb/in³ | Mass / length kg/m | lb/ft | vs carbon steel |
|---|---|---|---|---|---|
| Carbon Steel | 7,850 | 0.2836 | 2.355 | 1.582 | +0.0 % |
| Stainless Steel 304 | 8,000 | 0.2890 | 2.400 | 1.613 | +1.9 % |
| Stainless Steel 316 | 8,000 | 0.2890 | 2.400 | 1.613 | +1.9 % |
| Stainless Steel 316L | 8,000 | 0.2890 | 2.400 | 1.613 | +1.9 % |
| Stainless Steel 430 | 7,700 | 0.2782 | 2.310 | 1.552 | -1.9 % |
| Aluminum 6061-T6 | 2,700 | 0.0975 | 0.810 | 0.544 | -65.6 % |
| Aluminum 5052-H32 | 2,680 | 0.0968 | 0.804 | 0.540 | -65.9 % |
| Aluminum 7075-T6 | 2,810 | 0.1015 | 0.843 | 0.566 | -64.2 % |
| Copper C11000 | 8,940 | 0.3230 | 2.682 | 1.802 | +13.9 % |
| Brass C36000 | 8,500 | 0.3071 | 2.550 | 1.714 | +8.3 % |
| Bronze C93200 | 8,800 | 0.3179 | 2.640 | 1.774 | +12.1 % |
| Titanium Grade 2 | 4,510 | 0.1629 | 1.353 | 0.909 | -42.5 % |
| Gray Cast Iron | 7,200 | 0.2601 | 2.160 | 1.451 | -8.3 % |
| Lead | 11,340 | 0.4097 | 3.402 | 2.286 | +44.5 % |
| Rigid PVC (Type I) | 1,400 | 0.0506 | 0.420 | 0.282 | -82.2 % |
| HDPE (PE 100) | 960 | 0.0347 | 0.288 | 0.194 | -87.8 % |
Same geometry throughout, so the only variable is density. Carbon steel is highlighted as the baseline.
A note on using this table for costing: mass is not price. Aluminium is roughly a third of steel's mass here, but per kilogram it costs several times more, so a straight swap rarely saves money — what it buys is reduced load on a structure or a vehicle.
About aluminum 6061-t6
The general-purpose structural aluminium: magnesium and silicon alloyed, precipitation-hardened to T6, readily welded and machined. At 2,700 kg/m³ it is 2.91 times lighter than carbon steel, which is the entire reason it gets specified — but designers routinely forget that its modulus is also only about a third of steel’s, so a straight aluminium-for-steel swap cuts mass by 66 % while roughly tripling deflection for the same section. Weight savings and stiffness are separate problems.
- Density
- 2,700 kg/m³ = 0.0975 lb/in³ · 0.3439× carbon steel · typical spread ±1 %
- Specification
- ASTM B221 / B209 (T6 temper)
- Equivalents
- EN AW-6061 · JIS A6061 · GB 6061
- Typical uses
- Aircraft and drone frames · Marine decking and masts · Machine guards and jigs · Truck and trailer bodies
About flat bar
Flat bar is where the site’s most common estimating mistake shows up: weight is independent of how the bar is oriented, but stiffness is not. A 50 × 6 flat bent about its strong axis is roughly 69 times stiffer than the same bar bent about its weak axis, while both weigh 2.36 kg/m. Reading weight off a flat-bar table tells you what to order; it tells you nothing about whether the section will carry the load.
Specified as width × thickness. Edge condition (square, radiused, or sheared) changes the effective area slightly, not the nominal weight.
Download this data
AL 6061 flat bar — CSV
Both buttons below read the tables rendered on this page, so the file matches what you are looking at. The full catalogue — all 16 materials across all 10 sections — is on the downloads page.
Fields are quoted per RFC 4180, with a UTF-8 byte-order mark so Excel reads the mm² and · characters correctly. Blank lines separate the weight matrix from the area matrix.
Frequently asked questions
How much does aluminum 6061-t6 flat bar weigh?
At the reference dimensions (w = 50 mm, t = 6 mm) a aluminum 6061-t6 flat bar of this size weighs 0.810 kg/m, or 0.544 lb/ft. The table above lists the figure for every standard size so you can read your size directly instead of scaling.
How is the weight of flat bar calculated?
Weight is cross-sectional area × length × density. For this shape the area is A = w · t. At the reference dimensions that gives 300.0 mm², and multiplying by aluminum 6061-t6's density of 2,700 kg/m³ gives 0.810 kg/m. Nothing is looked up in a table — which is why a non-standard size is calculated just as accurately as a standard one.
Why does aluminum 6061-t6 weigh more or less than steel?
It is lighter than carbon steel for the same section — about 66 % lighter at 2,700 kg/m³. Density is the only variable: the cross-sectional area depends purely on geometry, so a flat bar of the same dimensions has the same area in every material and the mass simply scales with density. In this case the ratio is 0.3439× carbon steel.
What is the cross-sectional area of a flat bar?
The area depends only on the dimensions, not on the material, so it is identical whichever material you select: at the reference dimensions it is 300.0 mm² (0.4650 in²). That is the number you would enter into a stress or deflection calculation, and it is why changing material on this page never changes the area column.
Does a al 6061 flat bar weigh the same as a al 6061 part of a different shape?
No, and the difference is larger than most people expect. At equal nominal size, a square bar is 27.3 % heavier than a round bar, and a hollow section is typically 60–80 % lighter than the solid bar it replaces. Weight follows area, and area changes faster than dimensions do — which is exactly why this needs calculating rather than estimating.
Should I use AL 6061 weight or carbon steel weight for costing?
Use the material you are actually buying. At 2,700 kg/m³ against carbon steel's 7,850 kg/m³, the same flat bar differs by 65.6 % in mass. On a per-metre quote that is invisible; on a fabricated tonnage it is the difference between a margin and a loss. This page computes the steel figure as 2.355 kg/m for comparison.
Other materials, same flat bar
The same geometry in every material, so the only variable is density.
- Carbon steel flat bar — 7850 kg/m³
- SS 304 flat bar — 8000 kg/m³
- SS 316 flat bar — 8000 kg/m³
- Copper flat bar — 8940 kg/m³
- Brass flat bar — 8500 kg/m³
- HDPE flat bar — 960 kg/m³
- PVC flat bar — 1400 kg/m³
- AL 5052 flat bar — 2680 kg/m³
Other AL 6061 sections
The same density applied to every shape the site covers.
- AL 6061 round bar — A = π/4 · d²
- AL 6061 square bar — A = a²
- AL 6061 hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- AL 6061 plate — A = w · t
- AL 6061 round tube — A = π/4 · (D² − d²), d = D − 2t
- AL 6061 square tube — A = a² − (a − 2t)²
Reference data and tools
- Metal weight overview — how the calculation works
- All 16 materials — densities and specifications
- All 10 sections — formulas and size series
- Density chart — lightest to heaviest
- Metal weight calculator — any size, any material
- All calculators — metal weight and pipe weight
- Download the data — CSV, generated from the same source
- Cross-reference tables — DN / NPS / material equivalents
- Methodology and sources — where every number comes from
Flat Bar area from A = w · t. Mass computed as area × length × density at 2,700 kg/m³ (ASTM B221 / B209 (T6 temper)). No weight on this page is copied from a published table — which is why figures can differ in the last significant digit from a mill's chart calculated at a nominal density.
- Elementary plane geometry. The circle, polygon and hollow-section area formulas.
- ASTM material specifications for each grade named in the material entry (A36, A240/A276, B209/B211/B221, B152/B16/B505, B265/B348, A48, B29, D1784, D3350).
- BIPM / NIST definitional constants: international inch = 25.4 mm, foot = 0.3048 m, pound = 0.45359237 kg.
Dataset version 2026.09.1 · dimensions last verified against source 2026-09-21. Found an error? Report it — corrections are issued with a version bump.