Steel Round Bars: Sizes, Weight Chart, Prices & Specifications

Steel Round Bars: Sizes, Weight Chart, Prices & Specifications<\/h2>

Steel round bars — also called round bar steel, solid round bar, or round rod — are hot-rolled solid bars with a circular cross-section, used everywhere that strength, machinability, and simple geometry matter: shafts, pins, anchors, rebar alternatives, machine parts, and structural details. Because a solid round has the same strength in every direction and the highest section modulus per unit area of any simple bar shape, it is the default starting material for turned and machined components. This page is the complete buying reference from Sino East Steel Group — a direct steel structure manufacturer in Tianjin, China, exporting since 1993: round bar steel sizes, round bar weight charts, material grades, 2026 FOB price ranges, and the exact way to order round bars for your project.

1. What Is a Steel Round Bar?

A steel round bar is a solid, cylindrical bar produced by hot rolling billets through shaped rolls, then cooled, straightened, and cut to length. Diameters run from 8 mm fine bars up to 260 mm and beyond for heavy machining stock. Round bars are defined by diameter only, which makes dimension checking simple: a 50 mm round bar is exactly 50 mm in diameter along its full length, within the tolerances of EN 10060 or ASTM A6. The bars are supplied as-rolled (black, with mill scale), peeled, ground, or galvanized, in lengths of 6 m and 12 m, or cut to order.

Round bars are specified to material standards including EN 10025 (S235JR, S275JR, S355JR, S355J2), ASTM A36, ASTM A572 Gr 50, and GB/T 700 / GB/T 1591 (Q235B, Q355B), with dimensional tolerances per EN 10060 and ASTM A6. For projects requiring certified material, every bar is traceable to its heat number and ships with an EN 10204 3.1 mill test certificate.

2. Round Bar vs Square Bar vs Flat Bar: Which Bar Do You Need?

Comparison	Round Bar	Square Bar	Flat Bar
Cross-section	Solid circle	Solid square	Rectangle (width × thickness)
Dimensioning	Single diameter	Single side length	Two dimensions (w × t)
Strength	Equal in all directions; best for shafts/turning	Equal in two axes; good for keys, punches	Best in the flat axis; good for straps and gussets
Machining	Best — the starting stock for turned parts	Good — for milling, keys, dies	Limited — for sawing and drilling
Best for	Shafts, pins, anchors, machined components	Keys, punches, structural details, tooling	Straps, gussets, brackets, clamps, fencing
Typical use	Machine shafts, dowels, reinforcement	Handrails, grilles, mechanical parts	Fabrication plates, stair strings, earth bars

For turned, threaded, or rotating components, round bar is the only practical choice. If you need square or rectangular bar instead, see our Square Bars and Flat Bars pages.

3. Round Bar Sizes & Dimensions

Standard round bar steel sizes run from 8 mm to 260 mm diameter in regular increments. The table below lists the most commonly exported diameters with typical availability. Custom diameters, machined (peeled/ground) finishes, and cut lengths are produced to order.

Diameter (mm)	Imperial Equivalent	Typical Finish	Common Lengths
8	5/16″	Black / bright	6 / 12 m
10	3/8″	Black / bright	6 / 12 m
12	1/2″	Black / bright	6 / 12 m
16	5/8″	Black / bright	6 / 12 m
20	3/4″	Black / bright	6 / 12 m
25	1″	Black	6 / 12 m
30	1¼″	Black	6 / 12 m
40	1½″	Black	6 / 12 m
50	2″	Black	6 / 12 m
60	2½″	Black	6 / 12 m
80	3¼″	Black	6 / 12 m
100	4″	Black	6 / 12 m
120	4¾″	Black	6 / 12 m
150	6″	Black	6 / 12 m
200	8″	Black	6 / 12 m
260	10¼″	Black	6 / 12 m

Diameter tolerances follow EN 10060 and ASTM A6. For diameters above 60 mm, we recommend confirming the tolerance class (normal or precision) with your machinist before ordering — precision-ground bars are available for tight fits.

4. Round Bar Weight Chart (kg per Metre)

Indicative weights for common round bar steel sizes, calculated with the standard formula weight = π/4 × d² × 7.85 / 1000 kg/m (d = diameter in mm, 7.85 = steel density). Actual weights per EN 10060 are within ±3% of these values:

Diameter (mm)	Weight (kg/m)	Weight per 6 m (kg)	Weight per 12 m (kg)
10	0.62	3.70	7.40
12	0.89	5.33	10.66
16	1.58	9.48	18.95
20	2.47	14.81	29.61
25	3.85	23.12	46.25
30	5.55	33.30	66.60
40	9.86	59.18	118.37
50	15.41	92.46	184.93
60	22.20	133.20	266.40
80	39.46	236.76	473.52
100	61.65	369.90	739.80
120	88.78	532.68	1,065.36
150	138.72	832.32	1,664.64
200	246.62	1,479.72	2,959.44
260	416.78	2,500.68	5,001.36

Use the round bar weight chart to estimate tonnage and freight: multiply the kg/m figure by the total length. For example, 1,000 m of 50 mm round bar weighs about 15.41 tonnes; 1,000 m of 16 mm round bar weighs only 1.58 tonnes. A 40 ft container holds roughly 22–25 tonnes of round bar, bundled and strapped in uniform-diameter packs.

5. Round Bar Material Grades & Surface Options

Option	Specification	Best For
Mild steel	S235JR / Q235B — yield 235 MPa	General fabrication, dowels, anchors
Structural steel	S275JR — yield 275 MPa	Structural details, heavier members
High-strength steel	S355JR / S355J2 / Q355B — yield 355 MPa	Shafts, pins, highly loaded members
US grades	ASTM A36, ASTM A572 Gr 50	US project specifications
Galvanized	HDG 70–85 µm (ISO 1461) or pre-galvanized	Fencing, outdoor, coastal use
Surface finish	Black (as-rolled), peeled, precision ground, bright drawn	Machining stock, tight-tolerance fits

For shafts, pins, and machined parts, specify the finish that matches your final machining allowance: black bar for rough stock, peeled bar when scale must be removed, and ground bar when diameter tolerance is critical. Every batch ships with EN 10204 3.1 mill test certificates.

6. Round Bar Prices in 2026 (FOB China)

Indicative export pricing from our Tianjin factory (FOB Tianjin Port, 2026):

Product	Indicative Price	MOQ
Mild steel round bar (S235JR/Q235B), 8–50 mm	USD 550–700 per tonne FOB	5 tonnes (mix sizes OK)
Structural round bar (S275JR/S355JR), 50–260 mm	USD 580–750 per tonne FOB	5 tonnes
Galvanized round bar (HDG)	USD 680–880 per tonne FOB	10 tonnes
Peeled / ground / bright drawn finishes	USD 750–1,000 per tonne FOB	10 tonnes
Cutting to length, threading, drilling	Included or nominal charge	—

Prices move with global billet and scrap markets and exchange rates, so treat these as planning ranges. For a firm quotation send your diameters, steel grade, lengths, quantities, and destination port to paul@sinoeaststeel.com.

7. Round Bar Applications

• Shafts, axles, and spindles — solid round stock is the raw material for turned and machined rotating parts.
• Pins, dowels, and clevis parts — 8–50 mm round bar cut, chamfered, and threaded to order.
• Foundation bolts and anchor rods — bent and threaded round bar for steel building anchors.
• Concrete reinforcement details — round bar for stirrups, dowels, and connection details where rebar is not available.
• Handrails, balusters, and gates — galvanized round bar for ornamental and security fencing.
• Machine frames and bases — round bar spacers, stops, and adjustment rods.
• Mining and quarrying parts — drill stock, rod guides, and wear parts in carbon steel.

Round bar is part of our complete steel structure product range — for square or rectangular bar, see our Square Bars and Flat Bars pages; for tubular profiles, compare our Circular Hollow Section and Square Hollow Section pages.

8. Why Buy Round Bars Direct from Sino East Steel Group

Sino East Steel Group is a direct China steel structure manufacturer, not a trader. Since 1993 we have operated a 50,000 m² fabrication facility in Tianjin Industrial Park, Daqiuzhuang — China’s largest steel processing hub — with our own rolling mill supply chains, bar processing lines, and hot-dip galvanizing capacity.

• Factory-direct pricing — no middleman; typically 20–40% below regional re-seller prices.
• Certified quality — ISO 9001:2015, ISO 3834-2, EN 1090 EXC3/EXC4, AWS D1.1; mill test certificates on every batch.
• Full size range — 8 mm to 260 mm diameter, black, bright, peeled, or ground, lengths to 12 m.
• Value-added processing — cutting, chamfering, threading, drilling, bending, and galvanizing under one roof.
• Export documentation — invoice, packing list, certificate of origin, EN 10204 3.1 certificates for smooth clearance.
• 100,000+ tonnes annual capacity — standard diameters ship in 1–2 weeks; custom processing in 2–3 weeks.

Before committing to any factory, use our manufacturer verification checklist — we welcome third-party inspection (SGS, BV, TÜV) at any stage.

9. How to Order Round Bars from China

1. Send your diameter, steel grade, finish, length, quantity, and destination port.
2. Receive an itemized quotation within 24–48 hours (FOB/CIF).
3. Confirm tolerance class, coating, and mill certificate requirements.
4. We produce and test (SGS/BV/TÜV inspection optional).
5. We ship FCL from Tianjin with full export documentation.

For complete projects — round bar plus structural steel — see our procurement guide for importers.

10. Round Bar Machining & Fabrication Notes

When planning machining stock, allow for removal of the decarburized surface layer: for black bar, take at least 1.5 mm per side on small diameters; for peeled bar, 0.5–1.0 mm. Because round bar is supplied with mill scale unless specified, specify peeled or ground finish when the bar will be laser-cut or turned without a full cleanup pass. For threading, note that rolled threads are stronger than cut threads and can be supplied on bar ends up to 50 mm diameter. For bending, mild steel (S235JR/Q235B) forms reliably at diameters up to 60 mm cold; larger diameters require hot bending or induction heating — our shop can handle both.

For anchor rods and foundation bolts, always confirm the thread specification (metric coarse, UNC, or UNF), the embedded length, and the bend radius. Our engineers can provide bending, threading, and cutting schedules free of charge with your quotation request.

11. Packing, Shipping & Delivery

Round bars are bundled in uniform-diameter packs, strapped with steel bands, and loaded into 40 ft containers or break-bulk holds at Tianjin Port. Each bundle carries a tag with your project name, diameter, grade, and length for easy site sorting. Standard export documentation — commercial invoice, packing list, bill of lading, certificate of origin, and EN 10204 3.1 mill test certificates — is provided with every shipment.

Typical transit times: 3–4 weeks to the Middle East (Jebel Ali), 4–6 weeks to East and West Africa (Mombasa, Lagos), 4–5 weeks to Europe, and 3–5 weeks to North America. For full-project shipping details, read our international shipping and installation guide.

12. Round Bar FAQ

Q: What are the standard round bar steel sizes?
A: Standard diameters run from 8 mm to 260 mm in regular increments (10, 12, 16, 20, 25, 30, 40, 50, 60, 80, 100, 120, 150, 200, 260 mm). Lengths are 6 m or 12 m; custom cut lengths available.

Q: How do I calculate round bar weight per metre?
A: Use the formula π/4 × d² × 7.85 / 1000 kg/m. For example, a 25 mm round bar weighs about 3.85 kg/m and a 50 mm bar about 15.41 kg/m. Our weight chart above covers the full range.

Q: How much does round bar cost in 2026?
A: Indicative FOB China prices are USD 550–700 per tonne for mild steel round bar, USD 580–750 for structural grades, and USD 680–880 per tonne galvanized. Machined finishes cost more.

Q: Which steel grades are available for round bars?
A: S235JR, S275JR, S355JR, and S355J2 per EN 10025; Q235B and Q355B per GB/T 700 and GB/T 1591; ASTM A36 and A572 Gr 50 for US projects.

Q: What is the tolerance on round bar diameter?
A: Per EN 10060 and ASTM A6, normal tolerances apply to as-rolled black bar; precision-ground bar can be held to much tighter diameter tolerances for machining fits.

Q: Can round bars be galvanized?
A: Yes — hot-dip galvanized (HDG 70–85 µm per ISO 1461) for outdoor fencing, anchors, and coastal structures, or pre-galvanized bright bar.

Q: What is the difference between black, peeled, and ground round bar?
A: Black bar is as-rolled with mill scale; peeled bar has the surface layer removed for cleaner machining; ground bar is precision-machined to tight diameter tolerance and fine surface finish.

Q: Do you provide mill test certificates?
A: Yes — every batch ships with EN 10204 3.1 mill test certificates showing chemical composition and mechanical properties, plus certificate of origin and full export documentation.

Q: How do I get a round bar quotation?
A: Email your diameter, grade, finish, length, quantity, and destination port to paul@sinoeaststeel.com or message us on WhatsApp — you will receive an itemized FOB/CIF quotation within 48 hours.