Carbon Steel Hexagonal Bar Weight
Mass per metre and per foot for carbon steel hexagonal bar at 7,850 kg/m³ (ASTM A36 / AISI 1018 / EN 10025 S275). Every figure is for the section as drawn. A 6 m length of this size weighs 23.5 kg (52.6 lb per 20 ft).
At the reference dimensions (AF = 24 mm) this section has a cross-sectional area of 498.8 mm², giving 3.916 kg/m (2.631 lb/ft). This is the baseline density, so the figures here are what a steel weight chart shows.
Hexagonal Bar — formula and derivation
Area of a hexagonal bar
A = (√3/2) · AF² ≈ 0.8660 · AF²
A = (√3/2) × AF², where AF is the distance across flats (the wrench size), not across corners
Worked through with the default dimensions:
A = (√3/2) × AF²A = 0.866025 × 24²A = 0.866025 × 576.0A = 498.8 mm²
- AF
- Across flats (AF) — Distance between opposite flats — the size a spanner grips. Hex bar is ordered by AF, not by corner-to-corner.
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 7,850 kg/m³ that is 3.9158 kg/m for the reference size above.
Carbon steel hexagonal bar — size series
| Across flats (AF) | Cross-section | Mass / length |
|---|---|---|
| 5.0 mm | 21.65 mm² · 0.0336 in² | 0.170 kg/m · 0.114 lb/ft |
| 6.0 mm | 31.18 mm² · 0.0483 in² | 0.245 kg/m · 0.164 lb/ft |
| 8.0 mm | 55.43 mm² · 0.0859 in² | 0.435 kg/m · 0.292 lb/ft |
| 10 mm | 86.60 mm² · 0.1342 in² | 0.680 kg/m · 0.457 lb/ft |
| 12 mm | 124.71 mm² · 0.1933 in² | 0.979 kg/m · 0.658 lb/ft |
| 14 mm | 169.74 mm² · 0.2631 in² | 1.332 kg/m · 0.895 lb/ft |
| 17 mm | 250.28 mm² · 0.3879 in² | 1.965 kg/m · 1.320 lb/ft |
| 19 mm | 312.64 mm² · 0.4846 in² | 2.454 kg/m · 1.649 lb/ft |
| 22 mm | 419.16 mm² · 0.6497 in² | 3.290 kg/m · 2.211 lb/ft |
| 24 mm | 498.83 mm² · 0.7732 in² | 3.916 kg/m · 2.631 lb/ft |
| 27 mm | 631.33 mm² · 0.9786 in² | 4.956 kg/m · 3.330 lb/ft |
| 32 mm | 886.81 mm² · 1.3746 in² | 6.961 kg/m · 4.678 lb/ft |
| 36 mm | 1,122.37 mm² · 1.7397 in² | 8.811 kg/m · 5.920 lb/ft |
| 41 mm | 1,455.79 mm² · 2.2565 in² | 11.428 kg/m · 7.679 lb/ft |
| 46 mm | 1,832.51 mm² · 2.8404 in² | 14.385 kg/m · 9.666 lb/ft |
| 50 mm | 2,165.06 mm² · 3.3559 in² | 16.996 kg/m · 11.421 lb/ft |
Computed for Carbon steel at 7850 kg/m³ (0.2836 lb/in³). ASTM A36 / AISI 1018 / EN 10025 S275.
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.
Imperial sizes
Hexagonal Bar is also bought in inch sizes. The conversions below are exact (1 in = 25.4 mm by definition), so the metric equivalents are the true millimetre dimensions rather than a rounded nominal figure.
| Stock size | Metric equivalent mm | Cross-section | Mass / length |
|---|---|---|---|
| 1/4 in | 6.35 | 34.92 mm² · 0.0541 in² | 0.274 kg/m · 0.184 lb/ft |
| 5/16 in | 7.94 | 54.56 mm² · 0.0846 in² | 0.428 kg/m · 0.288 lb/ft |
| 3/8 in | 9.52 | 78.57 mm² · 0.1218 in² | 0.617 kg/m · 0.414 lb/ft |
| 7/16 in | 11.11 | 106.94 mm² · 0.1658 in² | 0.840 kg/m · 0.564 lb/ft |
| 1/2 in | 12.70 | 139.68 mm² · 0.2165 in² | 1.096 kg/m · 0.737 lb/ft |
| 9/16 in | 14.29 | 176.78 mm² · 0.2740 in² | 1.388 kg/m · 0.933 lb/ft |
| 5/8 in | 15.88 | 218.25 mm² · 0.3383 in² | 1.713 kg/m · 1.151 lb/ft |
| 3/4 in | 19.05 | 314.28 mm² · 0.4871 in² | 2.467 kg/m · 1.658 lb/ft |
| 7/8 in | 22.22 | 427.77 mm² · 0.6631 in² | 3.358 kg/m · 2.256 lb/ft |
| 1 in | 25.40 | 558.72 mm² · 0.8660 in² | 4.386 kg/m · 2.947 lb/ft |
| 1-1/4 in | 31.75 | 873.01 mm² · 1.3532 in² | 6.853 kg/m · 4.605 lb/ft |
| 1-1/2 in | 38.10 | 1,257.13 mm² · 1.9486 in² | 9.868 kg/m · 6.631 lb/ft |
| 2 in | 50.80 | 2,234.90 mm² · 3.4641 in² | 17.544 kg/m · 11.789 lb/ft |
Stock sizes in inches, converted exactly at 25.4 mm per inch. Material: Carbon Steel at 7850 kg/m³.
The same hexagonal bar in every material
Geometry is fixed and only density changes, so this table is the whole material-selection question in one view. Carbon Steel 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 | 3.916 | 2.631 | +0.0 % |
| Stainless Steel 304 | 8,000 | 0.2890 | 3.991 | 2.682 | +1.9 % |
| Stainless Steel 316 | 8,000 | 0.2890 | 3.991 | 2.682 | +1.9 % |
| Stainless Steel 316L | 8,000 | 0.2890 | 3.991 | 2.682 | +1.9 % |
| Stainless Steel 430 | 7,700 | 0.2782 | 3.841 | 2.581 | -1.9 % |
| Aluminum 6061-T6 | 2,700 | 0.0975 | 1.347 | 0.905 | -65.6 % |
| Aluminum 5052-H32 | 2,680 | 0.0968 | 1.337 | 0.898 | -65.9 % |
| Aluminum 7075-T6 | 2,810 | 0.1015 | 1.402 | 0.942 | -64.2 % |
| Copper C11000 | 8,940 | 0.3230 | 4.460 | 2.997 | +13.9 % |
| Brass C36000 | 8,500 | 0.3071 | 4.240 | 2.849 | +8.3 % |
| Bronze C93200 | 8,800 | 0.3179 | 4.390 | 2.950 | +12.1 % |
| Titanium Grade 2 | 4,510 | 0.1629 | 2.250 | 1.512 | -42.5 % |
| Gray Cast Iron | 7,200 | 0.2601 | 3.592 | 2.413 | -8.3 % |
| Lead | 11,340 | 0.4097 | 5.657 | 3.801 | +44.5 % |
| Rigid PVC (Type I) | 1,400 | 0.0506 | 0.698 | 0.469 | -82.2 % |
| HDPE (PE 100) | 960 | 0.0347 | 0.479 | 0.322 | -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 carbon steel
The baseline against which every other metal is compared. Mild and medium carbon steels sit at 7,850 kg/m³ across the usual structural and free-machining grades: A36 plate, 1018 shaft, S275JR section. Carbon content moves density so little over the 0.05–0.60 % range that one figure covers the family, which is why mill weight tables for "steel" almost always assume 7,850 kg/m³ (0.2836 lb/in³). Use this entry when the drawing says "steel" and no grade is called out.
- Density
- 7,850 kg/m³ = 0.2836 lb/in³ · 1.0000× carbon steel · typical spread ±1 %
- Specification
- ASTM A36 / AISI 1018 / EN 10025 S275
- Equivalents
- AISI 1018 · EN 1.0401 · JIS SS400 · GB Q235
- Typical uses
- Structural sections · Plate and bar stock · Fabricated weldments · Shafts and pins
Unprotected carbon steel corrodes at roughly 0.1 mm/year in a mild inland atmosphere and far faster in coastal or chemical service, so a corrosion allowance changes the mass you should order — not this density.
About hexagonal bar
Hex bar is the one shape where the ordering dimension is not the dimension the formula wants. Stock is sold by across-flats (AF) because that is what the wrench grips, but the area formula needs AF as well — and the two are easy to confuse once a drawing quotes across-corners instead. Across-corners is a factor of 2/√3 (1.1547) larger than AF, so mixing them up inflates the calculated weight by 33 %. Always check which one the drawing calls out.
Specified by across-flats. Say so explicitly on the order — "across corners" gives a different bar.
Download this data
Carbon steel hexagonal 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 carbon steel hexagonal bar weigh?
At the reference dimensions (AF = 24 mm) a carbon steel hexagonal bar of this size weighs 3.916 kg/m, or 2.631 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 hexagonal bar calculated?
Weight is cross-sectional area × length × density. For this shape the area is A = (√3/2) · AF² ≈ 0.8660 · AF². At the reference dimensions that gives 498.8 mm², and multiplying by carbon steel's density of 7,850 kg/m³ gives 3.916 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 carbon steel weigh more or less than steel?
It is the 7,850 kg/m³ baseline that every other figure on this site is measured against. Density is the only variable: the cross-sectional area depends purely on geometry, so a hexagonal 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 1.0000× carbon steel.
What is the cross-sectional area of a hexagonal 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 498.8 mm² (0.7732 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 carbon steel hexagonal bar weigh the same as a carbon steel 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.
Other materials, same hexagonal bar
The same geometry in every material, so the only variable is density.
- SS 304 hexagonal bar — 8000 kg/m³
- SS 316 hexagonal bar — 8000 kg/m³
- AL 6061 hexagonal bar — 2700 kg/m³
- Copper hexagonal bar — 8940 kg/m³
- Brass hexagonal bar — 8500 kg/m³
- HDPE hexagonal bar — 960 kg/m³
- PVC hexagonal bar — 1400 kg/m³
- AL 5052 hexagonal bar — 2680 kg/m³
Other Carbon steel sections
The same density applied to every shape the site covers.
- Carbon steel round bar — A = π/4 · d²
- Carbon steel square bar — A = a²
- Carbon steel flat bar — A = w · t
- Carbon steel plate — A = w · t
- Carbon steel round tube — A = π/4 · (D² − d²), d = D − 2t
- Carbon steel 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
Hexagonal Bar area from A = (√3/2) · AF² ≈ 0.8660 · AF². Mass computed as area × length × density at 7,850 kg/m³ (ASTM A36 / AISI 1018 / EN 10025 S275). 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.