Stainless Steel 316 Flat Bar Weight
Mass per metre and per foot for stainless steel 316 flat bar at 8,000 kg/m³ (ASTM A240 / A276 (UNS S31600)). Every figure is for the section as drawn. A 6 m length of this size weighs 14.4 kg (32.3 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 2.400 kg/m (1.613 lb/ft). Against carbon steel's 7,850 kg/m³ that is +1.9 % — 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 8,000 kg/m³ that is 2.4000 kg/m for the reference size above.
SS 316 flat bar — size series
| Width | 3.0 | 4.0 | 5.0 | 6.0 | 8.0 | 10 | 12 | 16 | 20 |
|---|---|---|---|---|---|---|---|---|---|
| 12 mm | 0.288 kg/m · 0.194 lb/ft | 0.384 kg/m · 0.258 lb/ft | 0.480 kg/m · 0.323 lb/ft | 0.576 kg/m · 0.387 lb/ft | 0.768 kg/m · 0.516 lb/ft | 0.960 kg/m · 0.645 lb/ft | 1.152 kg/m · 0.774 lb/ft | 1.536 kg/m · 1.032 lb/ft | 1.920 kg/m · 1.290 lb/ft |
| 16 mm | 0.384 kg/m · 0.258 lb/ft | 0.512 kg/m · 0.344 lb/ft | 0.640 kg/m · 0.430 lb/ft | 0.768 kg/m · 0.516 lb/ft | 1.024 kg/m · 0.688 lb/ft | 1.280 kg/m · 0.860 lb/ft | 1.536 kg/m · 1.032 lb/ft | 2.048 kg/m · 1.376 lb/ft | 2.560 kg/m · 1.720 lb/ft |
| 20 mm | 0.480 kg/m · 0.323 lb/ft | 0.640 kg/m · 0.430 lb/ft | 0.800 kg/m · 0.538 lb/ft | 0.960 kg/m · 0.645 lb/ft | 1.280 kg/m · 0.860 lb/ft | 1.600 kg/m · 1.075 lb/ft | 1.920 kg/m · 1.290 lb/ft | 2.560 kg/m · 1.720 lb/ft | 3.200 kg/m · 2.150 lb/ft |
| 25 mm | 0.600 kg/m · 0.403 lb/ft | 0.800 kg/m · 0.538 lb/ft | 1.000 kg/m · 0.672 lb/ft | 1.200 kg/m · 0.806 lb/ft | 1.600 kg/m · 1.075 lb/ft | 2.000 kg/m · 1.344 lb/ft | 2.400 kg/m · 1.613 lb/ft | 3.200 kg/m · 2.150 lb/ft | 4.000 kg/m · 2.688 lb/ft |
| 30 mm | 0.720 kg/m · 0.484 lb/ft | 0.960 kg/m · 0.645 lb/ft | 1.200 kg/m · 0.806 lb/ft | 1.440 kg/m · 0.968 lb/ft | 1.920 kg/m · 1.290 lb/ft | 2.400 kg/m · 1.613 lb/ft | 2.880 kg/m · 1.935 lb/ft | 3.840 kg/m · 2.580 lb/ft | 4.800 kg/m · 3.225 lb/ft |
| 40 mm | 0.960 kg/m · 0.645 lb/ft | 1.280 kg/m · 0.860 lb/ft | 1.600 kg/m · 1.075 lb/ft | 1.920 kg/m · 1.290 lb/ft | 2.560 kg/m · 1.720 lb/ft | 3.200 kg/m · 2.150 lb/ft | 3.840 kg/m · 2.580 lb/ft | 5.120 kg/m · 3.440 lb/ft | 6.400 kg/m · 4.301 lb/ft |
| 50 mm | 1.200 kg/m · 0.806 lb/ft | 1.600 kg/m · 1.075 lb/ft | 2.000 kg/m · 1.344 lb/ft | 2.400 kg/m · 1.613 lb/ft | 3.200 kg/m · 2.150 lb/ft | 4.000 kg/m · 2.688 lb/ft | 4.800 kg/m · 3.225 lb/ft | 6.400 kg/m · 4.301 lb/ft | 8.000 kg/m · 5.376 lb/ft |
| 60 mm | 1.440 kg/m · 0.968 lb/ft | 1.920 kg/m · 1.290 lb/ft | 2.400 kg/m · 1.613 lb/ft | 2.880 kg/m · 1.935 lb/ft | 3.840 kg/m · 2.580 lb/ft | 4.800 kg/m · 3.225 lb/ft | 5.760 kg/m · 3.871 lb/ft | 7.680 kg/m · 5.161 lb/ft | 9.600 kg/m · 6.451 lb/ft |
| 80 mm | 1.920 kg/m · 1.290 lb/ft | 2.560 kg/m · 1.720 lb/ft | 3.200 kg/m · 2.150 lb/ft | 3.840 kg/m · 2.580 lb/ft | 5.120 kg/m · 3.440 lb/ft | 6.400 kg/m · 4.301 lb/ft | 7.680 kg/m · 5.161 lb/ft | 10.240 kg/m · 6.881 lb/ft | 12.800 kg/m · 8.601 lb/ft |
| 100 mm | 2.400 kg/m · 1.613 lb/ft | 3.200 kg/m · 2.150 lb/ft | 4.000 kg/m · 2.688 lb/ft | 4.800 kg/m · 3.225 lb/ft | 6.400 kg/m · 4.301 lb/ft | 8.000 kg/m · 5.376 lb/ft | 9.600 kg/m · 6.451 lb/ft | 12.800 kg/m · 8.601 lb/ft | 16.000 kg/m · 10.752 lb/ft |
Rows: width (mm). Columns: thickness (mm). Computed for Stainless Steel 316 at 8000 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. Stainless Steel 316 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 stainless steel 316
Identical density to 304, so weight tables can be shared between them — but not material selection. The 2–3 % molybdenum addition is what buys resistance to chlorides and to the sulphuric and acetic acid environments that pit 304. For a weight take-off the two are interchangeable; for a coastal or process-chemical application they are not, and the substitution is usually made for the wrong reason (availability) without recalculating corrosion allowance.
- Density
- 8,000 kg/m³ = 0.2890 lb/in³ · 1.0191× carbon steel · typical spread ±1 %
- Specification
- ASTM A240 / A276 (UNS S31600)
- Equivalents
- EN 1.4401 · JIS SUS316 · GB 06Cr17Ni12Mo2
- Typical uses
- Marine and coastal hardware · Pharmaceutical and dairy process plant · Chemical storage and pipework · Pulp and paper
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
SS 316 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 stainless steel 316 flat bar weigh?
At the reference dimensions (w = 50 mm, t = 6 mm) a stainless steel 316 flat bar of this size weighs 2.400 kg/m, or 1.613 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 stainless steel 316's density of 8,000 kg/m³ gives 2.400 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 stainless steel 316 weigh more or less than steel?
It is heavier than carbon steel for the same section — about 2 % heavier at 8,000 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 1.0191× 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 ss 316 flat bar weigh the same as a ss 316 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 SS 316 weight or carbon steel weight for costing?
Use the material you are actually buying. At 8,000 kg/m³ against carbon steel's 7,850 kg/m³, the same flat bar differs by 1.9 % 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
- 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
- AL 5052 flat bar — 2680 kg/m³
Other SS 316 sections
The same density applied to every shape the site covers.
- SS 316 round bar — A = π/4 · d²
- SS 316 square bar — A = a²
- SS 316 hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- SS 316 plate — A = w · t
- SS 316 round tube — A = π/4 · (D² − d²), d = D − 2t
- SS 316 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 8,000 kg/m³ (ASTM A240 / A276 (UNS S31600)). 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.