HDPE (PE 100) Round Bar Weight
Mass per metre and per foot for hdpe (pe 100) round bar at 960 kg/m³ (ISO 4427 / ASTM D3350 (PE 100 black)). Every figure is for the section as drawn. A 6 m length of this size weighs 2.8 kg (6.3 lb per 20 ft).
At the reference dimensions (d = 25 mm) this section has a cross-sectional area of 490.9 mm², giving 0.471 kg/m (0.317 lb/ft). Against carbon steel's 7,850 kg/m³ that is -87.8 % — the same section in steel would be 3.853 kg/m.
Round Bar — formula and derivation
Area of a round bar
A = π/4 · d²
A = π/4 × d², where d is the outside diameter
Worked through with the default dimensions:
A = π/4 × d²A = 0.785398 × 25²A = 0.785398 × 625.0A = 490.9 mm²
- d
- Diameter — Outside diameter measured across the bar.
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 960 kg/m³ that is 0.4712 kg/m for the reference size above.
HDPE round bar — size series
| Diameter | Cross-section | Mass / length |
|---|---|---|
| 6.0 mm | 28.27 mm² · 0.0438 in² | 0.027 kg/m · 0.018 lb/ft |
| 8.0 mm | 50.27 mm² · 0.0779 in² | 0.048 kg/m · 0.032 lb/ft |
| 10 mm | 78.54 mm² · 0.1217 in² | 0.075 kg/m · 0.051 lb/ft |
| 12 mm | 113.10 mm² · 0.1753 in² | 0.109 kg/m · 0.073 lb/ft |
| 14 mm | 153.94 mm² · 0.2386 in² | 0.148 kg/m · 0.099 lb/ft |
| 16 mm | 201.06 mm² · 0.3116 in² | 0.193 kg/m · 0.130 lb/ft |
| 20 mm | 314.16 mm² · 0.4869 in² | 0.302 kg/m · 0.203 lb/ft |
| 25 mm | 490.87 mm² · 0.7609 in² | 0.471 kg/m · 0.317 lb/ft |
| 30 mm | 706.86 mm² · 1.0956 in² | 0.679 kg/m · 0.456 lb/ft |
| 32 mm | 804.25 mm² · 1.2466 in² | 0.772 kg/m · 0.519 lb/ft |
| 40 mm | 1,256.64 mm² · 1.9478 in² | 1.206 kg/m · 0.811 lb/ft |
| 50 mm | 1,963.50 mm² · 3.0434 in² | 1.885 kg/m · 1.267 lb/ft |
| 60 mm | 2,827.43 mm² · 4.3825 in² | 2.714 kg/m · 1.824 lb/ft |
| 80 mm | 5,026.55 mm² · 7.7912 in² | 4.825 kg/m · 3.243 lb/ft |
| 100 mm | 7,853.98 mm² · 12.1737 in² | 7.540 kg/m · 5.067 lb/ft |
Computed for HDPE at 960 kg/m³ (0.0347 lb/in³). ISO 4427 / ASTM D3350 (PE 100 black).
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
Round 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 |
|---|---|---|---|
| 1/8 in | 3.17 | 7.92 mm² · 0.0123 in² | 0.008 kg/m · 0.005 lb/ft |
| 3/16 in | 4.76 | 17.81 mm² · 0.0276 in² | 0.017 kg/m · 0.011 lb/ft |
| 1/4 in | 6.35 | 31.67 mm² · 0.0491 in² | 0.030 kg/m · 0.020 lb/ft |
| 5/16 in | 7.94 | 49.48 mm² · 0.0767 in² | 0.048 kg/m · 0.032 lb/ft |
| 3/8 in | 9.52 | 71.26 mm² · 0.1104 in² | 0.068 kg/m · 0.046 lb/ft |
| 1/2 in | 12.70 | 126.68 mm² · 0.1963 in² | 0.122 kg/m · 0.082 lb/ft |
| 5/8 in | 15.88 | 197.93 mm² · 0.3068 in² | 0.190 kg/m · 0.128 lb/ft |
| 3/4 in | 19.05 | 285.02 mm² · 0.4418 in² | 0.274 kg/m · 0.184 lb/ft |
| 7/8 in | 22.22 | 387.95 mm² · 0.6013 in² | 0.372 kg/m · 0.250 lb/ft |
| 1 in | 25.40 | 506.71 mm² · 0.7854 in² | 0.486 kg/m · 0.327 lb/ft |
| 1-1/4 in | 31.75 | 791.73 mm² · 1.2272 in² | 0.760 kg/m · 0.511 lb/ft |
| 1-1/2 in | 38.10 | 1,140.09 mm² · 1.7671 in² | 1.094 kg/m · 0.735 lb/ft |
| 2 in | 50.80 | 2,026.83 mm² · 3.1416 in² | 1.946 kg/m · 1.307 lb/ft |
| 2-1/2 in | 63.50 | 3,166.92 mm² · 4.9087 in² | 3.040 kg/m · 2.043 lb/ft |
| 3 in | 76.20 | 4,560.37 mm² · 7.0686 in² | 4.378 kg/m · 2.942 lb/ft |
| 4 in | 101.60 | 8,107.32 mm² · 12.5664 in² | 7.783 kg/m · 5.230 lb/ft |
Stock sizes in inches, converted exactly at 25.4 mm per inch. Material: HDPE (PE 100) at 960 kg/m³.
The same round bar in every material
Geometry is fixed and only density changes, so this table is the whole material-selection question in one view. HDPE (PE 100) 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 | 3.853 | 2.589 | +0.0 % |
| Stainless Steel 304 | 8,000 | 0.2890 | 3.927 | 2.639 | +1.9 % |
| Stainless Steel 316 | 8,000 | 0.2890 | 3.927 | 2.639 | +1.9 % |
| Stainless Steel 316L | 8,000 | 0.2890 | 3.927 | 2.639 | +1.9 % |
| Stainless Steel 430 | 7,700 | 0.2782 | 3.780 | 2.540 | -1.9 % |
| Aluminum 6061-T6 | 2,700 | 0.0975 | 1.325 | 0.891 | -65.6 % |
| Aluminum 5052-H32 | 2,680 | 0.0968 | 1.316 | 0.884 | -65.9 % |
| Aluminum 7075-T6 | 2,810 | 0.1015 | 1.379 | 0.927 | -64.2 % |
| Copper C11000 | 8,940 | 0.3230 | 4.388 | 2.949 | +13.9 % |
| Brass C36000 | 8,500 | 0.3071 | 4.172 | 2.804 | +8.3 % |
| Bronze C93200 | 8,800 | 0.3179 | 4.320 | 2.903 | +12.1 % |
| Titanium Grade 2 | 4,510 | 0.1629 | 2.214 | 1.488 | -42.5 % |
| Gray Cast Iron | 7,200 | 0.2601 | 3.534 | 2.375 | -8.3 % |
| Lead | 11,340 | 0.4097 | 5.567 | 3.741 | +44.5 % |
| Rigid PVC (Type I) | 1,400 | 0.0506 | 0.687 | 0.462 | -82.2 % |
| HDPE (PE 100) | 960 | 0.0347 | 0.471 | 0.317 | -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 hdpe (pe 100)
High-density polyethylene and the lightest material in the catalogue at 960 kg/m³ — it floats. That is not a curiosity: buoyancy governs how submerged outfall and intake lines are installed, and HDPE’s ability to be towed and floated into place in long strings is why it displaced steel for marine pipelines. It is also tougher than PVC at low temperature and tolerates ground movement without cracking, at the cost of much lower pressure rating at the same wall thickness.
- Density
- 960 kg/m³ = 0.0347 lb/in³ · 0.1223× carbon steel · typical spread ±2 %
- Specification
- ISO 4427 / ASTM D3350 (PE 100 black)
- Equivalents
- EN PE 100 · JIS PE100 · GB PE100
- Typical uses
- Water and gas mains · Submarine outfall lines · Landfill and leachate pipe · Geomembrane and lining
Density splits into two families: PE 100 pipe grades 950–960 kg/m³, PE 63/80 grades 930–945 kg/m³. Black compound includes ~2 % carbon black.
About round bar
Round bar is the only shape whose area grows with the square of a single dimension, so small diameter changes move weight much faster than intuition suggests: going from 25 mm to 28 mm — a 12 % diameter increase — raises the weight per metre by 25 %. This is why shaft stock is normally bought to the nearest preferred diameter rather than machined down from the next size up; the material saved is more than the weight table implies.
Specified by diameter only. For ground and polished stock, add the tolerance class and the straightness limit.
Download this data
HDPE round 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 hdpe (pe 100) round bar weigh?
At the reference dimensions (d = 25 mm) a hdpe (pe 100) round bar of this size weighs 0.471 kg/m, or 0.317 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 round bar calculated?
Weight is cross-sectional area × length × density. For this shape the area is A = π/4 · d². At the reference dimensions that gives 490.9 mm², and multiplying by hdpe (pe 100)'s density of 960 kg/m³ gives 0.471 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 hdpe (pe 100) weigh more or less than steel?
It is lighter than carbon steel for the same section — about 88 % lighter at 960 kg/m³. Density is the only variable: the cross-sectional area depends purely on geometry, so a round 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 0.1223× carbon steel.
What is the cross-sectional area of a round 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 490.9 mm² (0.7609 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 hdpe round bar weigh the same as a hdpe 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 HDPE weight or carbon steel weight for costing?
Use the material you are actually buying. At 960 kg/m³ against carbon steel's 7,850 kg/m³, the same round bar differs by 87.8 % 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 3.853 kg/m for comparison.
Other materials, same round bar
The same geometry in every material, so the only variable is density.
- Carbon steel round bar — 7850 kg/m³
- SS 304 round bar — 8000 kg/m³
- SS 316 round bar — 8000 kg/m³
- AL 6061 round bar — 2700 kg/m³
- Copper round bar — 8940 kg/m³
- Brass round bar — 8500 kg/m³
- PVC round bar — 1400 kg/m³
- AL 5052 round bar — 2680 kg/m³
Other HDPE sections
The same density applied to every shape the site covers.
- HDPE square bar — A = a²
- HDPE hexagonal bar — A = (√3/2) · AF² ≈ 0.8660 · AF²
- HDPE flat bar — A = w · t
- HDPE plate — A = w · t
- HDPE round tube — A = π/4 · (D² − d²), d = D − 2t
- HDPE 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
Round Bar area from A = π/4 · d². Mass computed as area × length × density at 960 kg/m³ (ISO 4427 / ASTM D3350 (PE 100 black)). 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.