Steel Unit Weight
Table
Unit weight values (kg/m) for round, hexagon, square, and flat steel bars.
Select Profile Type & Find Weight
| Diameter (mm) | kg/m | kg / 6m bar |
|---|---|---|
| 6 | 0.222 | 1.33 |
| 8 | 0.395 | 2.37 |
| 10 | 0.617 | 3.70 |
| 12 | 0.888 | 5.33 |
| 14 | 1.210 | 7.26 |
| 16 | 1.580 | 9.48 |
| 18 | 2.000 | 12.00 |
| 20 | 2.470 | 14.82 |
| 22 | 2.980 | 17.88 |
| 25 | 3.850 | 23.10 |
| 28 | 4.830 | 28.98 |
| 30 | 5.550 | 33.30 |
| 32 | 6.310 | 37.86 |
| 35 | 7.550 | 45.30 |
| 38 | 8.900 | 53.40 |
| 40 | 9.860 | 59.16 |
| 42 | 10.880 | 65.28 |
| 45 | 12.480 | 74.88 |
| 50 | 15.410 | 92.46 |
| 55 | 18.650 | 111.90 |
| 60 | 22.190 | 133.14 |
| 65 | 26.050 | 156.30 |
| 70 | 30.210 | 181.26 |
| 75 | 34.680 | 208.08 |
| 80 | 39.460 | 236.76 |
| 90 | 49.940 | 299.64 |
| 100 | 61.650 | 369.90 |
| 110 | 74.600 | 447.60 |
| 120 | 88.780 | 532.68 |
| 130 | 104.200 | 625.20 |
| 140 | 120.800 | 724.80 |
| 150 | 138.700 | 832.20 |
Calculation Formulas
Round Bar
W = d² x 0.006165
or W = (π/4) x d² x ρ / 1000
Hexagon
W = d² x 0.006798
Round weight x 1.103
Square Bar
W = d² x 0.00785
d = side length (mm)
Flat Bar
W = a x b x 0.00785
a = width, b = thickness (mm)
* All formulas calculated based on steel density ρ = 7.85 g/cm³. W = kg/m, d = mm
* Values calculated per EN 10060 with 7.85 g/cm³ density. Actual weights may vary ±3% depending on tolerances.
Steel Supply & Tonnage Calculation
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Get a QuoteHow to calculate steel unit weight?
The weight per meter of a steel profile (kg/m) = cross-sectional area (m²) × density (7,850 kg/m³). For a round bar, weight = 0.00617 × D² (D = diameter in mm) kg/m; Ø20 mm gives 2.47 kg/m. Square bar uses 0.00785 × a², and flat bar uses 0.00785 × width × thickness (in mm). Steel density is 7.85 g/cm³ for carbon and alloy steels.
Unit-weight formulas and use
Unit weight (weight per meter) is the mass of 1 meter of a steel profile — the base quantity for material, shipping and cost estimation. The logic is the same for every profile: compute the cross-section area, then multiply by steel density (7,850 kg/m³). Practical formulas (dimensions in mm, result kg/m): • Round: 0.00617 × D² • Square: 0.00785 × a² • Hexagon (across flats S): 0.00680 × S² • Flat bar: 0.00785 × width × thickness • Tube: 0.02466 × wall thickness × (outer diameter − wall thickness) Total weight = unit weight × length (m). Alloy composition changes density slightly; stainless steels (~7.9–8.0 g/cm³) give somewhat higher values.
Round Steel Bar Unit Weight Table (Carbon Steel, 7.85 g/cm³)
| Diameter (mm) | Weight (kg/m) | Area (mm²) |
|---|---|---|
| 6 | 0.222 | 28.3 |
| 8 | 0.395 | 50.3 |
| 10 | 0.617 | 78.5 |
| 12 | 0.888 | 113 |
| 14 | 1.21 | 154 |
| 16 | 1.58 | 201 |
| 18 | 2.00 | 254 |
| 20 | 2.47 | 314 |
| 25 | 3.85 | 491 |
| 30 | 5.55 | 707 |
| 35 | 7.55 | 962 |
| 40 | 9.86 | 1257 |
| 50 | 15.4 | 1964 |
| 60 | 22.2 | 2827 |
| 70 | 30.2 | 3848 |
| 80 | 39.5 | 5027 |
| 90 | 49.9 | 6362 |
| 100 | 61.7 | 7854 |
| 120 | 88.8 | 11310 |
| 150 | 139 | 17671 |
Formula: kg/m = 0.00617 × D². Values rounded to 3 significant figures.
Frequently Asked Questions
How much does 1 meter of Ø20 mm steel bar weigh?+
Using the round-bar formula 0.00617 × D²: 0.00617 × 20² = 2.47 kg/m. So 1 meter of Ø20 mm round steel bar weighs about 2.47 kg.
What is the steel unit-weight formula?+
Unit weight (kg/m) = cross-section area (m²) × 7,850 kg/m³. The practical form is 0.00617 × D² for round and 0.00785 × a² for square (D and a in mm).
Which density is used?+
7.85 g/cm³ (7,850 kg/m³) for carbon and alloy steels. Stainless steels are 7.9–8.0 g/cm³ and cast iron 7.0–7.3 g/cm³; for exact work use the value of the specific grade.
How is flat-bar weight found?+
For flat bar, unit weight = 0.00785 × width(mm) × thickness(mm) = kg/m. For example a 40×10 mm flat: 0.00785 × 40 × 10 = 3.14 kg/m.
How is pipe unit weight calculated?+
Pipe unit weight = 0.02466 × t × (D − t) kg/m, D = OD, t = wall thickness (mm). E.g. Ø60.3×3.91 mm (2" SCH40): 0.02466 × 3.91 × (60.3 − 3.91) = 5.44 kg/m.
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