The definitive reference for thread rod 8mm — weight, pitch, nominal dimensions, and the complete threaded rod size chart from M6 to M36. Whether you are a fabricator, contractor, or project engineer, this guide provides the key data for every standard fully-threaded rod size used in Indian construction and industrial work.
Need live pricing on thread rods and fasteners? Contact us directly for current rates.
Send EnquiryFill the contact form Join WhatsApp ChannelDaily rate updatesThis page is a complete technical reference for thread rod 8mm — covering its nominal weight of 0.395 kg/m, standard ISO metric thread pitch of 1.25 mm, dimensions as per IS 1367 and IS 4218, available grades (4.6, 8.8, 10.9), and the full threaded rod weight chart from M6 to M36. Whether you are estimating a consignment of anchor bolts, ordering all-thread rods for a suspended ceiling grid, or comparing grades for a structural connection — this reference gives you the data for every standard size at a glance. All nominal weight values are based on standard round-bar cross-sections at steel density 7.85 g/cm³.
Fully Threaded Rod • All-Thread Bar • IS 1367 • ISO Metric
A thread rod — also called a fully threaded rod, all-thread bar, or threaded bar — is a steel fastener rod that carries standard metric thread (helical groove) along its entire length. Unlike a bolt which has a smooth shank, a thread rod has no head and no smooth section — the thread runs continuously from one end to the other. The thread rod 8mm (designation M8) is one of the most commonly used sizes across Indian construction, MEP (mechanical-electrical-plumbing), and general fabrication work.
Fully Threaded Rod (All-Thread): The most common type — thread runs the entire length. Used for suspended pipe hangers, ceiling channel supports, anchor bolt extensions, and machine mounting. Available in standard stock lengths of 1 metre, cut as required on site.
Double-End Stud Bolt: Threaded at both ends with a plain shank in the middle. Used in flanged pipe joints, pressure vessel connections, and industrial bolted assemblies. The shank length and thread-end lengths are specified separately.
Anchor Thread Rod (Foundation Bolt): One end has an anchor mechanism (hook, plate, or upset head), the exposed end is threaded. Cast into concrete for column base plates, equipment plinths, and structural hold-downs.
The M8 thread rod (8mm nominal diameter) occupies a practical sweet spot in the fastener range:
• Light enough to cut with a hacksaw or angle grinder on site
• Strong enough for pipe hanger loads, ceiling suspension, and bracketing
• Compatible with M8 nuts, couplers, and channel nuts from all standard manufacturers
• Widely stocked across India — available at most hardware and steel suppliers
• Economical — the thread rod 8mm at 0.395 kg/m is among the most cost-effective fastening solutions per linear metre
Understanding the weight per metre helps you estimate consignment weight, freight cost, and per-piece cost from a per-tonne supplier price — the same conversion challenge found with structural sections.
Nominal Diameter • Pitch • Root Diameter • Thread Angle
Every value in the thread rod weight chart — including the thread rod 8mm weight of 0.395 kg/m — is derived from the nominal diameter (d) of the rod. The thread profile cuts into the surface, so the actual steel cross-section is slightly less than the full nominal circle. The diagram below shows the key parameters.
Nominal Diameter (d): The outside thread diameter in mm — what you specify when ordering. For M8, d = 8mm. This is the dimension used for weight calculations and is marked on all packaging and documentation.
Pitch (P): The axial distance between adjacent thread crests in mm. For M8 coarse thread, P = 1.25mm. This determines how far the rod advances per turn of a nut — critical for on-site cutting and assembly planning.
Root Diameter (d₂): The minor or root diameter at the base of the thread groove — for M8, approximately 6.83mm. This is the effective load-carrying cross-section for tensile strength calculations. Always refer to manufacturer data or IS 1367 for verified tensile stress area values.
All standard thread rods in India use the ISO metric thread form — a 60° thread angle with flat roots and crests. This is also referred to as the "M" thread series. The designation follows the format:
M8 × 1.25
M = Metric thread, 8 = Nominal diameter in mm, 1.25 = Pitch in mm.
When the pitch is not stated, it is understood to be the standard coarse pitch for that diameter. Fine pitch variants (e.g., M8 × 1.0) are available for precision applications and are always stated explicitly. Always confirm pitch with your supplier when ordering thread rods for precision fit-ups or high-load connections.
Thread rods in India are typically stocked in 1-metre lengths, though 2m and 3m full-thread bars are also available. Coupler nuts (threaded couplers) allow extending rods to any required length on site. Always specify required length clearly on your purchase order.
M8 • Nominal Weight 0.395 kg/m • Pitch 1.25mm • Grade 4.6 / 8.8
The thread rod 8mm (M8) is one of the most commonly used thread rod sizes in Indian construction and fabrication. It is the default size for pipe hanger assemblies, MEP suspended ceiling systems, lightweight bracket fixing, and general-purpose anchor applications. Here is the complete data reference for the M8 fully threaded rod.
| Thread Rod 8mm — M8 × 1.25 Reference | |
|---|---|
| Designation | M8 × 1.25 (coarse) |
| Nominal Diameter | 8.0 mm |
| Thread Pitch (coarse) | 1.25 mm |
| Thread Pitch (fine) | 1.0 mm (optional) |
| Root Diameter (approx.) | ≈ 6.83 mm |
| Thread Angle | 60° (ISO metric) |
| Nominal Weight / m | 0.395 kg/m |
| Weight per 1m piece | 0.395 kg |
| Weight per 3m bar | 1.185 kg |
| Governing Standard | IS 1367 / IS 4218 |
| Common Grades | 4.6, 8.8, 10.9 |
| Typical Stock Lengths | 1m, 2m, 3m |
| Size | Pitch (mm) | kg/m | kg/1m piece |
|---|---|---|---|
| M6 | 1.00 | 0.222 | 0.222 |
| M8 ★ FEATURED | 1.25 | 0.395 | 0.395 |
| M10 | 1.50 | 0.617 | 0.617 |
| M12 | 1.75 | 0.888 | 0.888 |
| M16 | 2.00 | 1.578 | 1.578 |
| M20 | 2.50 | 2.467 | 2.467 |
From M8 (0.395 kg/m) to M10 (0.617 kg/m) — a 56% increase. From M10 to M12 — a 44% increase. Thread rod weight scales with the square of the diameter, so small size increases produce significant weight and cost jumps. Always select the minimum size that meets your load requirement.
All Standard Metric Sizes • Nominal Weight kg/m • Pitch • Root Diameter
The following thread rod weight chart covers all standard metric fully-threaded rod sizes from M6 to M36. Weights are in kilograms per metre (kg/m) based on the nominal (full circular) cross-section at 7.85 g/cm³. The M8 (thread rod 8mm) row is highlighted. Colour coding: ■ lighter, ■ medium, ■ heavy.
| Size (Designation) |
Nominal Dia (mm) |
Coarse Pitch (mm) |
Root Dia (approx. mm) |
Nominal Weight (kg/m) |
Weight per 1m piece (kg) |
Weight per 3m bar (kg) |
|---|---|---|---|---|---|---|
| → Small Thread Rods — M6 to M10 | ||||||
| M6 | 6.0 | 1.00 | ≈4.92 | 0.222 | 0.222 | 0.666 |
| M8 ★ FEATURED | 8.0 | 1.25 | ≈6.83 | 0.395 | 0.395 | 1.185 |
| M10 | 10.0 | 1.50 | ≈8.16 | 0.617 | 0.617 | 1.851 |
| → Medium Thread Rods — M12 to M16 | ||||||
| M12 | 12.0 | 1.75 | ≈10.11 | 0.888 | 0.888 | 2.664 |
| M14 | 14.0 | 2.00 | ≈11.84 | 1.208 | 1.208 | 3.624 |
| M16 | 16.0 | 2.00 | ≈13.84 | 1.578 | 1.578 | 4.734 |
| → Large Thread Rods — M20 to M36 | ||||||
| M20 | 20.0 | 2.50 | ≈17.29 | 2.467 | 2.467 | 7.401 |
| M24 | 24.0 | 3.00 | ≈20.75 | 3.552 | 3.552 | 10.656 |
| M27 | 27.0 | 3.00 | ≈23.75 | 4.500 | 4.500 | 13.500 |
| M30 | 30.0 | 3.50 | ≈26.21 | 5.549 | 5.549 | 16.647 |
| M36 | 36.0 | 4.00 | ≈31.67 | 7.990 | 7.990 | 23.970 |
All weights in this chart are nominal values based on the full circular cross-section at 7.85 g/cm³. The actual weight of a fully-threaded rod is marginally lower (approximately 1–3%) because the thread groove removes a small amount of material. For project BOQ and freight estimation, the nominal values are widely accepted as the working standard. For high-precision quantity reconciliation, consult the manufacturer's certified weight data. The thread rod 8mm nominal weight of 0.395 kg/m is the standard reference used across the Indian steel and fastener trade.
Standard Formula • Derivation • Worked Examples
You can calculate the nominal weight of any round-section thread rod using a simple formula. This is the same formula behind all values in the thread rod weight chart — including the thread rod 8mm weight of 0.395 kg/m. Understanding it lets you quickly estimate non-standard diameters or verify chart values.
Given: d = 8 mm
Using d² ÷ 162:
Weight = 8² ÷ 162
= 64 ÷ 162
= 0.395 kg/m ✓
This confirms the chart value for thread rod 8mm. Full formula check:
= (π/4) × 0.008² × 7850
= 0.7854 × 0.000064 × 7850
= 0.3946 ≈ 0.395 kg/m ✓
Given: d = 16 mm
Weight = 16² ÷ 162
= 256 ÷ 162
= 1.580 kg/m ✓
Matches the chart value of 1.578 kg/m (minor rounding difference). Notice that doubling the diameter from 8mm to 16mm increases weight by 4× (400%) — because weight scales with the square of diameter. This is why selection of the right thread rod size is cost-critical for large-volume projects.
Thread rods are sold in bundles. For M8 in 1m lengths:
• Weight per piece: 0.395 kg
• Pieces per MT (1m lengths): 1,000 ÷ 0.395 = approx. 2,532 pieces per MT
• For 3m bars: 1,000 ÷ 1.185 = approx. 844 bars per MT
Use these figures to cross-check supplier invoices and estimate freight weight for project consignments.
Grade Selection • Mechanical Properties • Marking & Identification
Thread rod grade is separate from thread rod size. A thread rod 8mm is available in multiple grades — and the grade determines the mechanical strength, not the weight. Weight is governed by the diameter; grade governs what load the rod can safely carry. Here is a practical grade guide.
The most commonly stocked grade of thread rod in India. Suitable for pipe hangers, ceiling suspension struts, light bracket fixing, non-structural bolted connections, and general fabrication. Grade 4.6 means minimum yield strength of 240 N/mm² and minimum tensile strength of 400 N/mm². For a thread rod 8mm in Grade 4.6, this provides adequate capacity for most standard hanger and suspension applications.
Used where higher load capacity is required in the same diameter. Grade 8.8 thread rods (quenched and tempered medium-carbon steel) offer minimum yield strength of 640 N/mm² — more than 2.6× Grade 4.6. Required for structural bolted connections, equipment anchor rods under dynamic loads, and applications where the engineer specifies a minimum fastener grade. Always verify grade marking on the rod end or bundle tag before use in structural applications.
Alloy steel, quenched and tempered, with minimum yield strength of 900 N/mm². Used in prestressed anchor applications, heavy machinery hold-downs, bridge components, and high-load structural connections. Grade 10.9 thread rods require design by a qualified structural engineer and installation by trained personnel. Not for general use without engineering validation.
Stainless steel fully threaded rods (Grade A2-70 or A4-80) are used in corrosive environments — marine, chemical plants, coastal construction, and food-processing facilities where mild steel would corrode. Stainless thread rods cost significantly more than mild steel equivalents. Weight per metre is nearly identical to MS (density 7.9–8.0 g/cm³ for austenitic grades vs 7.85 for MS).
IS 1367 requires grade markings on fasteners. On thread rods, this is typically stamped or embossed on the end face or at regular intervals along the rod. Grade 8.8 is also identified by a colour-coded end marking system used by some manufacturers — but colour coding is not standardised and should not be used as the sole verification method. Always request a Mill Test Certificate (MTC) from your supplier for grade-critical applications and structural use.
Construction • MEP • Industrial • Infrastructure
Thread rods are among the most versatile fastening products in the construction and industrial supply chain. Their fully-threaded profile allows adjustment, extension with coupler nuts, and custom-length cutting — advantages that bolts and studs with fixed lengths cannot offer. Here is how different sizes, including the thread rod 8mm, map to real-world applications across India.
Rooftop solar panel mounting systems routinely use M8 thread rods for panel rail clips, ballast frame connection points, and roof anchor inserts. M10–M12 used for primary rail-to-roof structure connections. Hot-dip galvanised or stainless grade preferred for all outdoor installations.
Formwork tie rods (through-bolts) use M12–M20 thread rods to resist concrete pour pressure. Sacrificial PVC sleeves protect the rod in the poured section. The protruding ends are cut after striking. Thread rod weight is important here as tie rods are often procured by weight, not piece count.
Rail fastening systems, bridge bearing anchor rods, signalling gantry foundations, and overhead electrical mast hold-downs use heavy-grade thread rods. These are always engineer-specified with material certification requirements and strict installation torque standards.
Fully Threaded Rod • Anchor Bolt • Double-End Stud • Comparison
Buyers frequently compare thread rods, anchor bolts, and stud bolts for the same application — particularly in construction and MEP work. Here is a direct comparison to help you specify correctly.
| Parameter | Thread Rod (All-Thread) | Anchor Bolt (Foundation Bolt) | Stud Bolt (Double-End) | Best For |
|---|---|---|---|---|
| Thread coverage | Full length — thread end to end | One end threaded, one end anchored (hook/plate) | Both ends threaded, plain shank in middle | Context-dependent |
| Head / anchor mechanism | None — uses nuts on both sides | Hook, L-bend, or welded plate cast in concrete | None — shoulder nut or nut on both ends | Anchor bolt — concrete embedment |
| Adjustability on site | ✔ Excellent — cut to any length, extend with coupler nut | Limited — embedment depth fixed at pour stage | Fixed shank length — limited thread zone only | ✔ Thread rod |
| Use for suspension / hanger | ✔ Standard — M8 thread rod is the industry default for pipe hangers | Not typically used for suspension | Not typically used for suspension | ✔ Thread rod |
| Use in flanged pipe joints | Can be used with nuts on both sides | Not suitable | ✔ Preferred — shank centres in flange bore, thread zones engage nuts | Stud bolt — flanges |
| Cost per metre | Most economical — simple form, high volume production | More expensive — custom bent or welded anchor end | Medium — machined shank required | ✔ Thread rod |
| Weight (for M8 size) | 0.395 kg/m (same formula for all) | Slightly more — anchor end adds mass | 0.395 kg/m for threaded portion | Similar — based on dia |
| Procurement | Widely stocked — all hardware & steel suppliers | Usually made-to-order for specific embedment depth | Stocked in standard configurations; custom available | ✔ Thread rod — immediate availability |
Per-MT to Per-Piece Conversion • Specification Language • Common Errors
Thread rods are sold by weight (per kg or per MT) at the wholesale and mill level, but procured by piece count or bundle on site. The thread rod 8mm weight of 0.395 kg/m is the conversion key between these two worlds. Here is a practical procurement guide.
Step-by-step example for thread rod 8mm in 1m lengths:
Step 1: Get per-MT price from supplier.
Example: ₹95,000 per MT (Grade 4.6, M8)
Step 2: Weight of one 1m piece = 0.395 kg
Step 3: Per-piece rate = (95,000 ÷ 1,000) × 0.395
= 95 × 0.395 = ₹37.53 per piece
Step 4: For 3m bars: 95 × 1.185 = ₹112.58 per bar
With this benchmark you can evaluate any supplier's per-piece or per-bundle quote directly and identify whether you are being charged a fair per-kg equivalent.
1. Not specifying grade: "M8 thread rod" without a grade means the supplier may supply Grade 4.6 when Grade 8.8 was intended for a structural application. Always state the grade explicitly.
2. Not specifying surface finish: Plain (black), zinc-plated (electro-galvanised), hot-dip galvanised, and stainless steel thread rods look similar in a bundle but differ significantly in corrosion performance and cost. State the required finish.
3. Confusing nominal diameter with thread size: An M8 thread rod has a nominal diameter of 8mm — but the root (minor) diameter is only ~6.83mm. If you are drilling a hole to pass an M8 rod through, you need a hole of at least 8.4–9mm, not 6.83mm.
Product: Fully Threaded Rod (All-Thread)
Designation: M8 × 1.25 (Coarse Pitch)
Length: 1000mm (1 metre) per piece
Grade: 4.6 (per IS 1367)
Finish: Plain (Black) / Zinc Plated / HDG [specify]
Standard: IS 1367:1980 / IS 4218
Certification: MTC required with delivery
• Bureau of Indian Standards (BIS) — IS 1367: Technical Supply Conditions for Threaded Steel Fasteners
• Bureau of Indian Standards (BIS) — IS 4218: ISO Metric Screw Threads — Dimensions
• Ministry of Steel, Government of India — Steel industry standards and policy information
FAQ • For Fabricators, Contractors & Steel Traders
Vishwageeta Ispat is Raipur's trusted iron and steel stockist — supplying TMT bars, MS angles, ISMC channels, I-beams, MS round pipes (IS 1239), square MS pipes (IS 4923), rectangular hollow sections, GI pipes, MS sheets, chequered plates, and structural steel products. This thread rod 8mm reference guide is published as a free technical resource for contractors, fabricators, project engineers, and procurement teams across Chhattisgarh and Central India.
Need current rates on thread rods, fasteners, or any structural steel product? Our team provides mill-linked, competitive pricing. Call, WhatsApp, or fill the enquiry form — we respond the same working day.