Reinforcing bar is one of the most traded steel products. This guide explains the common grades and standards, gives the nominal cross-sectional areas and weights per meter, and shows what an export shipment of rebar involves.
Rebar is ribbed steel bar that reinforces concrete; in Europe the usual grade is B500 with a yield strength of at least 500 MPa.
Weight per meter follows from the diameter: kg/m ≈ 0.00617 × d², so a 12 mm bar weighs about 0.888 kg/m.
An export lot is defined by standard and grade, sizes, lengths, bundling, marking, mill certificate EN 10204 3.1 and inspection.
Rebar (reinforcing bar) is steel bar with ribs on its surface, embedded in concrete to carry tensile forces. The ribs bond the bar to the concrete.
Concrete resists compression well but cracks under tension. Rebar takes over that tension in slabs, beams, columns, foundations and walls. It is supplied as straight bars, as coils for further processing and as welded mesh. Rebar is carbon steel; its properties are set by the product standard, not by the trade name.
In Europe, EN 10080 is the common framework, while the grades themselves are defined nationally, mostly as B500 variants. In the United States, ASTM A615 and ASTM A706 apply, with Grade 60 as the usual grade.
Which standard applies is decided by the country of the construction project and its approvals, not by the producer. The standard and grade belong in the contract.
Metric rebar is designated by nominal diameter, usually 6 to 40 mm. The cross-sectional area of steel is A = π × d² / 4 and the weight per meter follows from a steel density of 7,850 kg/m³.
| Nominal diameter (mm) | Area of steel (mm²) | Weight (kg/m) |
|---|---|---|
| 6 | 28.3 | 0.222 |
| 8 | 50.3 | 0.395 |
| 10 | 78.5 | 0.617 |
| 12 | 113 | 0.888 |
| 14 | 154 | 1.21 |
| 16 | 201 | 1.58 |
| 20 | 314 | 2.47 |
| 25 | 491 | 3.85 |
| 28 | 616 | 4.83 |
| 32 | 804 | 6.31 |
| 40 | 1257 | 9.86 |
Nominal values. Binding are the standard and the contract, including the permitted mass tolerance. Engineers use the area of steel to size reinforcement; buyers use the weight per meter to convert tonnes into meters of bar.
Multiply the square of the diameter in millimetres by 0.00617: kg/m ≈ 0.00617 × d². A 16 mm bar weighs about 1.58 kg/m, so a 12 m bar weighs about 19 kg.
The factor 0.00617 is π/4 × 7,850 kg/m³ expressed in mm² and meters. Practical use:
US bar numbers give the nominal diameter in eighths of an inch up to #8: #4 is 4/8 = 1/2 inch. From #9 upward the number is only a designation; #14 has a nominal diameter of 1.693 inches (about 43 mm).
| Bar no. | Nominal diameter | Area | Weight (kg/m) |
|---|---|---|---|
| #3 | 0.375 in (9.5 mm) | 0.11 in² (71 mm²) | 0.56 |
| #4 | 0.500 in (12.7 mm) | 0.20 in² (129 mm²) | 0.99 |
| #5 | 0.625 in (15.9 mm) | 0.31 in² (200 mm²) | 1.55 |
| #6 | 0.750 in (19.0 mm) | 0.44 in² (284 mm²) | 2.24 |
| #8 | 1.000 in (25.4 mm) | 0.79 in² (510 mm²) | 3.97 |
| #10 | 1.270 in (32.3 mm) | 1.27 in² (819 mm²) | 6.40 |
| #11 | 1.410 in (35.8 mm) | 1.56 in² (1006 mm²) | 7.91 |
| #14 | 1.693 in (43.0 mm) | 2.25 in² (1452 mm²) | 11.38 |
| #18 | 2.257 in (57.3 mm) | 4.00 in² (2581 mm²) | 20.24 |
Nominal values according to ASTM A615/A706, converted to metric; binding are the standard and the contract. #14 and #18 are large sizes for heavy structures and are not rolled by every mill.
Rebar steel is made either from iron ore in a blast furnace and converter, or from scrap in an electric arc furnace. The steel is cast into billets, which are hot-rolled into ribbed bars.
The production route also determines the CO₂ footprint, which matters for CBAM on imports into the EU.
Rebar is sold with a mill certificate, usually type 3.1 under EN 10204. It shows yield strength, tensile-to-yield ratio, elongation at maximum force, chemical composition and the heat number.
For B500 the characteristic yield strength is at least 500 MPa. Ductility is described by the ratio Rm/Re and the elongation at maximum force (Agt). The ductility classes of Eurocode 2 are commonly given as:
| Class | Rm/Re (k) | Agt | Typical grade |
|---|---|---|---|
| A | ≥ 1.05 | ≥ 2.5 % | B500A |
| B | ≥ 1.08 | ≥ 5.0 % | B500B |
| C | ≥ 1.15 and < 1.35 | ≥ 7.5 % | B500C, B500SD |
Characteristic values; binding is the standard named in the contract, including its national annex. The certificate must match the heat numbers on the bundle labels. An independent inspection can check this before shipment, see inspection and certificates.
Export quality means the lot meets an agreed standard and grade, is bundled, tagged and marked, and is documented by certificates. The export procedure runs from specification through inspection and loading to shipping documents.
Import into the EU: rebar falls under CBAM, so the importer needs the status of authorised CBAM declarant and emission data from the producer. Steel imports are also subject to trade measures such as tariff quotas or anti-dumping duties, depending on origin. The current status for each origin and tariff code is shown in TARIC.
Large lots come from mills and from trading companies, under a contract per shipment. A request should state standard, grade, sizes, quantity per size, delivery term, port and required documents.
Andalucia Premium SL in Málaga brokers between verified companies and does not trade on its own account or hold stock. A complete request contains:
More on the steel sector, or send your request via the contact page.
Last updated: October 2026This page provides general information about trade practice. It is not legal, tax or investment advice.
Rebar is carbon steel, made from iron ore in a blast furnace and converter or from scrap in an electric arc furnace, then hot-rolled into ribbed bars.
B stands for reinforcing steel and 500 for the characteristic yield strength of at least 500 MPa. The letter after it, such as A, B, C, S or SD, indicates ductility class or weldability depending on the national standard.
Nominally 50.3 mm² for 8 mm, 113 mm² for 12 mm, 201 mm² for 16 mm, 314 mm² for 20 mm and 491 mm² for 25 mm. The formula is π × d² / 4.
Multiply the weight per meter by 12: based on nominal values, a 12 mm bar weighs about 10.7 kg, a 16 mm bar about 19 kg and a 25 mm bar about 46 kg.
A #14 bar has a nominal diameter of 1.693 inches (about 43 mm), an area of 2.25 square inches and a nominal weight of 7.650 lb per foot (about 11.4 kg/m).
No. Grade 60 has a minimum yield strength of about 420 MPa and different ductility rules. Whether a bar may be used depends on the standard and approvals of the project country.
Usually a commercial invoice, packing list, bill of lading, mill certificate EN 10204 3.1, certificate of origin and, if agreed, an independent inspection report.
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