How is steel round bar weight calculated?

Steel round bar weight per foot is calculated using: W (lb/ft) = d² × 2.676, where d = diameter in inches. Derivation: area A = πd²/4, weight density = 490 lb/ft³ / 144 in²/ft² = 3.40 lb per in² per foot. W = A × 3.40 = (πd²/4) × 3.40 = d² × π × 3.40/4 = d² × 2.676. Quick reference: 1/2 in bar → W = 0.5² × 2.676 = 0.67 lb/ft. 3/4 in → 0.75² × 2.676 = 1.50 lb/ft. 1 in → 1² × 2.676 = 2.67 lb/ft (the constant 2.676 is numerically close to 2.67 — weight in lb/ft ≈ 2.67 × d²). 1-1/2 in → 1.5² × 2.676 = 6.01 lb/ft. 2 in → 4 × 2.676 = 10.68 lb/ft. 3 in → 9 × 2.676 = 24.03 lb/ft. 4 in → 16 × 2.676 = 42.73 lb/ft. A 20 ft length of 1 in round bar weighs 20 × 2.67 = 53.4 lb. For metric: kg/m ≈ d_mm² × 0.00616. Standard mill lengths: 20 ft and 24 ft for hot-rolled bars, 12 ft and 20 ft for cold-drawn. Coils available for diameters up to 1 in. The weight scales with d² — doubling the diameter quadruples the weight. A 2 in bar weighs 4× as much per foot as a 1 in bar (10.68 vs 2.67 lb/ft). For project estimating: count total linear feet × weight per foot for each diameter, add 5-10% for waste and connections.

What is the difference between round bar, threaded rod, and anchor bolts?

Round bar, threaded rod, and anchor bolts serve different purposes and have different design bases: Round bar — hot-rolled solid cylindrical bar with smooth surface. ASTM A36 (Fy = 36 ksi, Fu = 58 ksi) or A572 Gr 50 (Fy = 50 ksi, Fu = 65 ksi). Used for shafts, pins, bollards, and bending members. Design tensile capacity based on full cross-sectional area A = πd²/4. Threaded rod — continuous threading along the entire length or partial threading. ASTM A307 Gr A (Fu = 60 ksi), A193 B7 (Fy = 105, Fu = 125 ksi), A449 (Fy = 92, Fu = 120 ksi). Used for tension-only applications: hanger rods, tie rods, brace rods. Design tensile capacity based on net (root) area at threads: An = π/4 × (D − 0.9743/n)² where n = threads per inch. For 3/4 in UNC (n = 10): An = π/4 × (0.75 − 0.9743/10)² = 0.334 in² vs gross area 0.442 in² — 24% reduction. Anchor bolts (F1554) — typically threaded at the top end only (partial thread), with a smooth shank embedded in concrete. ASTM F1554 has three grades: Gr 36 (Fy = 36, Fu = 58), Gr 55 (Fy = 55, Fu = 75), Gr 105 (Fy = 105, Fu = 125). Designed per ACI 318 Appendix D (now Chapter 17) for concrete breakout, pullout, and side-face blowout in addition to steel strength. The embedment depth in concrete (typically 8-12× diameter) governs capacity, not just the steel area. Key distinction: round bar for bending/shear, threaded rod for tension only, anchor bolts for concrete anchorage where embedment governs.

What ASTM specifications apply to steel round bars and what are their strengths?

Steel round bar specifications by application: General structural — A36: Fy = 36 ksi, Fu = 58 ksi. Most common general-purpose round bar for shafts, pins, bollards, and miscellaneous fabrication. A572 Gr 50: Fy = 50 ksi, Fu = 65 ksi. 39% higher yield strength than A36, allowing smaller diameters for same load or higher capacity for same diameter. Cost premium ~10-15% over A36. Bolting and threaded applications — A307 Gr A: Fu = 60 ksi (no specified Fy). General-purpose carbon steel bolts and threaded rod for non-structural connections. A193 B7: Fy = 105 ksi, Fu = 125 ksi. High-temperature alloy steel bolting (Cr-Mo) for pressure vessels, flanges, and structural applications above 400°F. A193 B8 (Type 304 stainless): Fy = 30 ksi, Fu = 75 ksi. Stainless steel for corrosion resistance. A449: Fy = 92 ksi, Fu = 120 ksi. High-strength bolting for structural connections where A325/A490 dimensions don't apply. A325 (heavy hex): Fy = 92 ksi, Fu = 120 ksi. Standard structural bolts for bearing-type connections. A490 (heavy hex): Fy = 120 ksi, Fu = 150 ksi. High-strength structural bolts (not galvanizeable). Anchor bolts — F1554 Gr 36: Fy = 36 ksi, Fu = 58 ksi. Weldable (low carbon), standard for light-to-medium anchor bolts. F1554 Gr 55: Fy = 55 ksi, Fu = 75 ksi. Higher strength, weldable with low-carbon equivalent. Most common for structural column anchor bolts. F1554 Gr 105: Fy = 105 ksi, Fu = 125 ksi. High-strength, NOT weldable (high carbon equivalent). For heavy-duty anchor bolts where welding is not required. For structural round bars in bending/torsion (shafts, pins), use A36 or A572. For tension rods, use A449 or A193 B7. For anchor bolts embedded in concrete, use F1554.

What diameter round bar is needed for anchor bolts and tie rods?

Anchor bolt and tie rod sizing follows application-specific guidelines: Anchor bolts for column base plates (F1554 Gr 55): typical diameters: 3/4 in for light columns (W8-W10, Pu < 100 kips), 7/8 in for medium columns (W12, Pu 100-200 kips), 1 in for standard columns (W14, Pu 200-400 kips), 1-1/4 in for heavy columns (W14, Pu 400-600 kips), 1-1/2 in + for very heavy columns or uplift-governed designs. Minimum embedment in concrete: 8× diameter for Gr 36, 10-12× for Gr 55. Approximate tension capacity (F1554 Gr 55, steel strength only): 3/4 in → 6.4 kips, 1 in → 11.4 kips, 1-1/4 in → 17.8 kips, 1-1/2 in → 25.6 kips, 2 in → 45.5 kips. These are steel-only values — concrete breakout capacity (per ACI 318 Chapter 17) typically governs for smaller embedment depths. Anchor bolt minimum embedment: per ACI 318, h_ef_min ≥ 6 in for headed anchors, and ≥ 8×d for bolts with nuts. For post-installed anchors (epoxy or expansion), follow manufacturer ESR report. Tie rods (A36 or A449): typical diameters: 5/8 in for light bracing (10-15 kips), 3/4 in (15-25 kips), 1 in (30-45 kips), 1-1/4 in (45-70 kips), 1-1/2 in (70-100 kips). Tension capacity = φ × Fu × An where φ = 0.75 per AISC J3.6 and An = net area at threads. For 1 in A36 threaded rod: An ≈ 0.606 in², φTn = 0.75 × 58 × 0.606 = 26.4 kips. Rods must be checked for both gross section yielding (φ × Fy × Ag) and net section rupture at threads (φ × Fu × An). The net area at threads typically governs for threaded rods. Sag rods (roof purlin bracing): typically 1/2 in or 5/8 in diameter, tension-only, A36, spaced at purlin third points to brace the purlin bottom flange against lateral-torsional buckling.

Can steel round bar be bent and what are the minimum bend radii?

Steel round bar can be cold-bent or hot-bent depending on diameter and bend radius: Cold bending (ambient temperature, no heating): suitable for diameters up to approximately 1-1/2 in. Minimum bend radius: 3× to 5× bar diameter for A36 steel. For 1 in bar: minimum inside bend radius = 3 in (3× dia). For 1-1/2 in bar: minimum inside bend radius = 4.5-7.5 in. Cold bending induces residual stresses and work-hardening at the bend — the yield strength increases locally (up to 15-20% increase) but ductility decreases. This is acceptable for static applications but may reduce fatigue life. Hot bending (heat to 815-925°C / 1500-1700°F, bend while hot, air cool): required for larger diameters (>1-1/2 in) and tighter radii (<3× dia). Hot bending eliminates work-hardening but may affect material properties if the cooling rate is too rapid (normalizing may be required after). Post-bend heat treatment: if the bend radius is tighter than 3× dia or if the bar is heat-treated (quenched and tempered), stress-relieving at 600-650°C (1100-1200°F) for 1 hour per inch of diameter may be required to reduce residual stresses. For anchor bolts with a 90° hook: the standard hook is formed hot or cold per ASTM F1554. The hook length = 4× dia minimum beyond the tangent point. The bend radius for F1554 hooks = 2× dia for bars ≤ 1 in, 3× dia for bars > 1 in. For reinforcing bars (rebar): minimum bend diameters per ACI 318 Table 25.3.1 — 6× bar diameter for #3-#8 bars. Rebar bending is standard practice and does not require post-bend heat treatment. For shafts and pins subject to fatigue: avoid cold bends in fatigue-critical applications. Use hot-formed bends with post-bend normalizing, or machine the part from larger stock to achieve the desired shape without bending.

Steel Round Bar Sizes — Diameter & Weight Chart

Q: Can steel round bar be bent and what are the minimum bend radii?

Steel round bar can be cold-bent or hot-bent depending on diameter and bend radius: Cold bending (ambient temperature, no heating): suitable for diameters up to approximately 1-1/2 in. Minimum bend radius: 3× to 5× bar diameter for A36 steel. For 1 in bar: minimum inside bend radius = 3 in (3× dia). For 1-1/2 in bar: minimum inside bend radius = 4.5-7.5 in. Cold bending induces residual stresses and work-hardening at the bend — the yield strength increases locally (up to 15-20% increase) but ductility decreases. This is acceptable for static applications but may reduce fatigue life. Hot bending (heat to 815-925°C / 1500-1700°F, bend while hot, air cool): required for larger diameters (>1-1/2 in) and tighter radii (<3× dia). Hot bending eliminates work-hardening but may affect material properties if the cooling rate is too rapid (normalizing may be required after). Post-bend heat treatment: if the bend radius is tighter than 3× dia or if the bar is heat-treated (quenched and tempered), stress-relieving at 600-650°C (1100-1200°F) for 1 hour per inch of diameter may be required to reduce residual stresses. For anchor bolts with a 90° hook: the standard hook is formed hot or cold per ASTM F1554. The hook length = 4× dia minimum beyond the tangent point. The bend radius for F1554 hooks = 2× dia for bars ≤ 1 in, 3× dia for bars > 1 in. For reinforcing bars (rebar): minimum bend diameters per ACI 318 Table 25.3.1 — 6× bar diameter for #3-#8 bars. Rebar bending is standard practice and does not require post-bend heat treatment. For shafts and pins subject to fatigue: avoid cold bends in fatigue-critical applications. Use hot-formed bends with post-bend normalizing, or machine the part from larger stock to achieve the desired shape without bending.

Steel round bars (also called rounds or round stock) are solid cylindrical bars used for shafts, pins, bolts, anchors, tie rods, and miscellaneous structural applications. This page provides standard sizes, weights, and selection guidance for hot-rolled steel round bars.

Weight Calculation

Weight per foot (lb/ft) = d² × 2.676

where d = diameter in inches. This comes from the area of a circle (πd²/4) times the unit weight of steel (490 lb/ft³ / 144 in²/ft²).

Weight per foot (lb/ft) = π × d² / 4 × 3.40

where 3.40 = 490 / 144 (lb/ft³ converted to lb per in² per foot of length).

Standard Round Bar Sizes and Weights

Small Rounds (1/4 in to 1 in)

Diameter (in)	Weight (lb/ft)	Area (in²)	Circumference (in)	Common Use
1/4	0.17	0.049	0.79	Pins, dowels
5/16	0.26	0.077	0.98	Small pins
3/8	0.38	0.110	1.18	Bolts, pins
7/16	0.51	0.150	1.37	Tie rods (light)
1/2	0.67	0.196	1.57	Bolts, anchors
9/16	0.85	0.249	1.77	Anchor bolts
5/8	1.04	0.307	1.96	Tie rods, bolts
3/4	1.50	0.442	2.36	Anchor bolts, shafts
7/8	2.04	0.601	2.75	Shafts, pins
1	2.67	0.785	3.14	Shafts, tie rods

Medium Rounds (1-1/8 in to 2 in)

Diameter (in)	Weight (lb/ft)	Area (in²)	Common Use
1-1/8	3.38	0.994	Shafts, pump rods
1-1/4	4.17	1.227	Anchor bolts, shafts
1-3/8	5.05	1.485	Shafts
1-1/2	6.01	1.767	Tie rods, anchor bolts
1-5/8	7.07	2.074	Shafts, pins
1-3/4	8.18	2.405	Tie rods, bollards
1-7/8	9.39	2.761	Shafts
2	10.68	3.142	Anchor bolts, tie rods

Large Rounds (2-1/4 in to 6 in)

Diameter (in)	Weight (lb/ft)	Area (in²)	Common Use
2-1/4	13.52	3.976	Anchor bolts
2-1/2	16.69	4.909	Anchor bolts, tie rods
2-3/4	20.23	5.940	Heavy anchor bolts
3	24.03	7.069	Bollards, anchor bolts
3-1/4	28.22	8.296	Heavy anchors
3-1/2	32.73	9.621	Bollards
3-3/4	37.60	11.045	Heavy shafts
4	42.73	12.566	Bollards, king pins
4-1/2	54.12	15.904	Heavy anchors
5	66.82	19.635	Foundation bolts
5-1/2	80.81	23.758	Heavy equipment
6	96.17	28.274	Large bollards, pins

Extra-Large Rounds (7 in to 12 in)

Diameter (in)	Weight (lb/ft)	Area (in²)
7	130.8	38.485
8	170.9	50.265
9	216.4	63.617
10	267.3	78.540
11	323.5	95.033
12	385.0	113.097

Extra-large rounds are typically special-order from the mill. Availability varies significantly by producer.

ASTM Specifications

Spec	Grade	Fy (ksi)	Fu (ksi)	Common Use
A36	—	36	58	General purpose rounds
A572	Gr 50	50	65	Higher strength structural
A193	B7	105	125	High-temperature bolting
A193	B8 (304)	30	75	Stainless steel bolts
A325	—	92	120	Structural bolting (heavy hex)
A490	—	120	150	High-strength structural bolting
A449	—	92	120	Anchor bolts, threaded rod
A307	Gr A	—	60	General purpose bolts
F1554	Gr 36	36	58	Anchor bolts (foundation)
F1554	Gr 55	55	75	Anchor bolts (foundation)
F1554	Gr 105	105	125	Anchor bolts (heavy duty)

Threaded Rod vs Round Bar

Feature	Round Bar	Threaded Rod
Surface	Smooth	Threaded (full or partial)
Available in	All diameters	Typically 1/4 to 3 in
ASTM	A36, A572	A307, A193, A449
Use	Shafts, pins, bending	Tension rods, hanger assemblies
Capacity basis	Full cross-section area	Root (net) area at threads
Tensile area	πd²/4	π/4 × (D - 0.9743/n)²

Anchor Bolt Sizes (F1554)

Diameter (in)	Thread Length (in)	Min Embedment (in)	Allowable Tension (kips)	Allowable Shear (kips)
3/4	3	6	6.4	3.7
7/8	3.5	7	8.7	5.0
1	4	8	11.4	6.5
1-1/4	4.5	10	17.8	10.2
1-1/2	5	12	25.6	14.7
1-3/4	6	14	34.8	20.0
2	6.5	16	45.5	26.1
2-1/2	7.5	20	71.1	40.8
3	9	24	102.3	58.7

Values shown for F1554 Gr 55 with ACI 318 Appendix D method. Allowable values use φ factors and include concrete breakout capacity. Actual capacity depends on concrete strength, edge distance, and spacing.

Available Lengths

Form	Standard Lengths
Hot-rolled bars	20 ft, 24 ft (mill standard)
Cold-drawn bars	12 ft, 20 ft
Cut pieces	Per order (6 in to 24 ft)
Coils	Continuous (up to 1 in dia)

Design Applications

Application	Typical Diameter	ASTM Spec	Design Consideration
Anchor bolts	3/4 to 2-1/2	F1554	ACI 318 Appendix D, embedment depth
Tie rods	5/8 to 2	A36, A449	Tension on net area at threads
Shafts	1 to 6	A36, A572	Torsion, bending, fatigue
Bollards	4 to 8	A36	Impact load, base plate weld
Pins	1/2 to 3	A36	Bearing, shear, bending
Hanger rods	1/2 to 1-1/2	A193 B7	Tension, thread engagement
Dowels	1/4 to 1	A36	Shear transfer
Clevis pins	3/4 to 2-1/2	A36	Shear, bearing

Weight per Length Quick Reference

Length	1 in dia (lb)	1-1/2 in dia (lb)	2 in dia (lb)	3 in dia (lb)
1 ft	2.67	6.01	10.68	24.03
3 ft	8.01	18.03	32.05	72.08
10 ft	26.70	60.10	106.80	240.27
20 ft	53.40	120.20	213.60	480.54

Frequently Asked Questions

How much does a 1-inch steel round bar weigh per foot? 2.67 lb/ft. A 20-foot bar weighs approximately 53.4 lb.

What is the difference between A36 and A572 round bar? A36 has Fy = 36 ksi and is the most common general purpose round bar. A572 Grade 50 has Fy = 50 ksi, providing 39% more yield strength for the same cross section. A572 costs slightly more but allows smaller diameters for the same load.

What size round bar is used for anchor bolts? Foundation anchor bolts are typically 3/4 to 2-1/2 inches in diameter, conforming to ASTM F1554. The most common sizes for steel column base plates are 3/4, 7/8, and 1 inch. Heavy equipment anchors may use 2 to 3 inch diameters.

How do I calculate the tensile capacity of a round bar? For a smooth round bar: P = Fu × A, where Fu is the tensile strength and A = πd²/4. For threaded rod, use the net tensile area at the threads: An = π/4 × (D - 0.9743/n)², where n is threads per inch. Per AISC, use φ = 0.75 for LRFD.

Can round bar be bent? Yes. Small rounds (up to 1 in) can be bent cold with standard equipment. Larger rounds require heat bending or mechanical equipment. Minimum bend radius is typically 3 to 5 times the diameter for cold bending.

Steel Weight Calculator — Weight by dimensions
Steel Flat Bar Sizes — Flat bar weight chart
Bolted Connections — Connection design
Steel Weight per Foot — All shapes chart
Anchor Bolt Embedment — Anchor bolt design

Disclaimer

This is a calculation tool, not a substitute for professional engineering certification. All results must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) before use in construction, fabrication, or permit documents. The user is responsible for the accuracy of all inputs and the verification of all outputs.