Lead Flat Bar Weight
Mass per metre and per foot for lead flat bar at 11,340 kg/m³ (ASTM B29 (UNS L50049, chemical lead)). Every figure is for the section as drawn. A 6 m length of this size weighs 20.4 kg (45.7 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 3.402 kg/m (2.286 lb/ft). Against carbon steel's 7,850 kg/m³ that is +44.5 % — 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 11,340 kg/m³ that is 3.4020 kg/m for the reference size above.
Lead flat bar — size series
| Width | 3.0 | 4.0 | 5.0 | 6.0 | 8.0 | 10 | 12 | 16 | 20 |
|---|---|---|---|---|---|---|---|---|---|
| 12 mm | 0.408 kg/m · 0.274 lb/ft | 0.544 kg/m · 0.366 lb/ft | 0.680 kg/m · 0.457 lb/ft | 0.816 kg/m · 0.549 lb/ft | 1.089 kg/m · 0.732 lb/ft | 1.361 kg/m · 0.914 lb/ft | 1.633 kg/m · 1.097 lb/ft | 2.177 kg/m · 1.463 lb/ft | 2.722 kg/m · 1.829 lb/ft |
| 16 mm | 0.544 kg/m · 0.366 lb/ft | 0.726 kg/m · 0.488 lb/ft | 0.907 kg/m · 0.610 lb/ft | 1.089 kg/m · 0.732 lb/ft | 1.452 kg/m · 0.975 lb/ft | 1.814 kg/m · 1.219 lb/ft | 2.177 kg/m · 1.463 lb/ft | 2.903 kg/m · 1.951 lb/ft | 3.629 kg/m · 2.438 lb/ft |
| 20 mm | 0.680 kg/m · 0.457 lb/ft | 0.907 kg/m · 0.610 lb/ft | 1.134 kg/m · 0.762 lb/ft | 1.361 kg/m · 0.914 lb/ft | 1.814 kg/m · 1.219 lb/ft | 2.268 kg/m · 1.524 lb/ft | 2.722 kg/m · 1.829 lb/ft | 3.629 kg/m · 2.438 lb/ft | 4.536 kg/m · 3.048 lb/ft |
| 25 mm | 0.850 kg/m · 0.572 lb/ft | 1.134 kg/m · 0.762 lb/ft | 1.417 kg/m · 0.953 lb/ft | 1.701 kg/m · 1.143 lb/ft | 2.268 kg/m · 1.524 lb/ft | 2.835 kg/m · 1.905 lb/ft | 3.402 kg/m · 2.286 lb/ft | 4.536 kg/m · 3.048 lb/ft | 5.670 kg/m · 3.810 lb/ft |
| 30 mm | 1.021 kg/m · 0.686 lb/ft | 1.361 kg/m · 0.914 lb/ft | 1.701 kg/m · 1.143 lb/ft | 2.041 kg/m · 1.372 lb/ft | 2.722 kg/m · 1.829 lb/ft | 3.402 kg/m · 2.286 lb/ft | 4.082 kg/m · 2.743 lb/ft | 5.443 kg/m · 3.658 lb/ft | 6.804 kg/m · 4.572 lb/ft |
| 40 mm | 1.361 kg/m · 0.914 lb/ft | 1.814 kg/m · 1.219 lb/ft | 2.268 kg/m · 1.524 lb/ft | 2.722 kg/m · 1.829 lb/ft | 3.629 kg/m · 2.438 lb/ft | 4.536 kg/m · 3.048 lb/ft | 5.443 kg/m · 3.658 lb/ft | 7.258 kg/m · 4.877 lb/ft | 9.072 kg/m · 6.096 lb/ft |
| 50 mm | 1.701 kg/m · 1.143 lb/ft | 2.268 kg/m · 1.524 lb/ft | 2.835 kg/m · 1.905 lb/ft | 3.402 kg/m · 2.286 lb/ft | 4.536 kg/m · 3.048 lb/ft | 5.670 kg/m · 3.810 lb/ft | 6.804 kg/m · 4.572 lb/ft | 9.072 kg/m · 6.096 lb/ft | 11.340 kg/m · 7.620 lb/ft |
| 60 mm | 2.041 kg/m · 1.372 lb/ft | 2.722 kg/m · 1.829 lb/ft | 3.402 kg/m · 2.286 lb/ft | 4.082 kg/m · 2.743 lb/ft | 5.443 kg/m · 3.658 lb/ft | 6.804 kg/m · 4.572 lb/ft | 8.165 kg/m · 5.486 lb/ft | 10.886 kg/m · 7.315 lb/ft | 13.608 kg/m · 9.144 lb/ft |
| 80 mm | 2.722 kg/m · 1.829 lb/ft | 3.629 kg/m · 2.438 lb/ft | 4.536 kg/m · 3.048 lb/ft | 5.443 kg/m · 3.658 lb/ft | 7.258 kg/m · 4.877 lb/ft | 9.072 kg/m · 6.096 lb/ft | 10.886 kg/m · 7.315 lb/ft | 14.515 kg/m · 9.754 lb/ft | 18.144 kg/m · 12.192 lb/ft |
| 100 mm | 3.402 kg/m · 2.286 lb/ft | 4.536 kg/m · 3.048 lb/ft | 5.670 kg/m · 3.810 lb/ft | 6.804 kg/m · 4.572 lb/ft | 9.072 kg/m · 6.096 lb/ft | 11.340 kg/m · 7.620 lb/ft | 13.608 kg/m · 9.144 lb/ft | 18.144 kg/m · 12.192 lb/ft | 22.680 kg/m · 15.240 lb/ft |
Rows: width (mm). Columns: thickness (mm). Computed for Lead at 11340 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. Lead 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 lead
The densest material in the catalogue at 11,340 kg/m³ — 44 % heavier than carbon steel — and used precisely for that. Lead sheet is specified for acoustic and radiation shielding, where the performance metric is mass per unit area, so a sheet weight table is not an incidental output here, it is the design input: 1 mm of lead is about 11.34 kg/m². It is also extremely soft and creeps under sustained load, so it is normally supported, not self-carrying.
- Density
- 11,340 kg/m³ = 0.4097 lb/in³ · 1.4446× carbon steel · typical spread ±1 %
- Specification
- ASTM B29 (UNS L50049, chemical lead)
- Equivalents
- EN PB000 · GB Pb1
- Typical uses
- Radiation shielding · Acoustic and vibration isolation · Roof flashing and damp courses · Battery plates
Heavy-metal hazard: machining, welding and dross handling require controls. Creeps under its own weight at ambient temperature.
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
Lead 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 lead flat bar weigh?
At the reference dimensions (w = 50 mm, t = 6 mm) a lead flat bar of this size weighs 3.402 kg/m, or 2.286 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 lead's density of 11,340 kg/m³ gives 3.402 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 lead weigh more or less than steel?
It is heavier than carbon steel for the same section — about 44 % heavier at 11,340 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 1.4446× 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 lead flat bar weigh the same as a lead 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 Lead weight or carbon steel weight for costing?
Use the material you are actually buying. At 11,340 kg/m³ against carbon steel's 7,850 kg/m³, the same flat bar differs by 44.5 % 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
- AL 6061 flat bar — 2700 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
Other Lead sections
The same density applied to every shape the site covers.
- Lead round bar — A = π/4 · d²
- Lead square bar — A = a²
- Lead hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- Lead plate — A = w · t
- Lead round tube — A = π/4 · (D² − d²), d = D − 2t
- Lead 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 11,340 kg/m³ (ASTM B29 (UNS L50049, chemical lead)). 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.