Copper Wire Weight Calculator — IS 8130:2013 (0.5 to 240 sqmm, Class 2 + Class 5)

H1: Copper Weight Calculator — Per Metre, Per 100m, Per 1000m Reference (IS 8130:2013)

The copper weight of a single-core conductor in kilograms per metre is given by the canonical formula kg/m = sq.mm × 0.00896 × stranding_factor, where the constant 0.00896 is the mass of a 1 mm² × 1 m volume of electrolytic-tough-pitch (ETP) copper at 8.96 g/cm³, and the stranding factor accounts for inter-strand voids — approximately 1.02 for Class 2 stranded and 1.04 for Class 5 fine-stranded conductors per IS 8130:2013. The 18-row reference table below covers every standard cross-section from 0.5 sqmm to 240 sqmm with kg/m, kg/100m, kg/1000m values for both classes, plus the IS 8130:2013 maximum DC resistance at 20 °C — the same values an MEP engineer pulls from the standard when verifying a quote, building a freight estimate, or back-checking the copper-floor model behind a price.

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How copper weight per metre is calculated

A copper conductor is a cylinder of metal whose cross-sectional area, by definition, is the nominal sqmm rating of the cable. To convert area to mass per unit length, only two things matter: the density of the copper and the geometric efficiency of how strands pack into the bundle.

Step 1 — density. Electrolytic-tough-pitch copper, the grade specified for IS 694:2010 building wires and IS 1554 Part 1 power cables, has a standard density of 8.96 g/cm³ (8,960 kg/m³). Wikipedia and the BIS conductor specification both adopt this value; small variations between annealed and hard-drawn copper are below 0.1% and are ignored at the standard level. Step 2 — area to volume. A 1 mm² cross-section extruded along 1 metre is a volume of 1 mm² × 1000 mm = 1,000 mm³ = 1 cm³. Multiplied by 8.96 g/cm³, this gives 8.96 g/m per mm² of solid copper, or 0.00896 kg/m per sqmm. This is the constant that anchors every copper-weight table in the industry. Step 3 — stranding factor. A Class 1 solid conductor has zero inter-strand voids and uses 0.00896 directly. A Class 2 stranded conductor (7 wires for sizes ≤16 sqmm, 19 wires for 25–95 sqmm, 37 wires for 120–240 sqmm) has small triangular voids between adjacent strands that reduce effective copper volume — but the nominal sqmm rating in IS 8130:2013 is the resistance-equivalent area, which means the manufacturer must add slightly more copper to compensate. The net effect is a multiplier of ≈1.02 (a 2% uplift). A Class 5 flexible conductor uses much finer wires (typically 0.21 mm for 2.5 sqmm flexible) packed in a rope-lay construction with 4–5% void compensation, giving a multiplier of ≈1.04. Class 6, used in the finest welding cables and panel internal wiring, runs ≈1.05. Worked example — 2.5 sqmm Class 2:

> 2.5 × 0.00896 × 1.02 = 0.02285 kg/m = 22.85 g/m

Over a standard 100 m coil that is 2.285 kg of copper. Over a 1000 m drum it is 22.85 kg. Multiply by the LME-anchored ₹/kg copper price (see /copper-price-india) to get the raw-material floor of any copper-only BOQ line.

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Reference table — IS 8130:2013 conductor weight and resistance

The table below lists conductor weight only (no insulation, no armour, no sheath). Class 2 = stranded fixed-installation conductor, Class 5 = fine-stranded flexible conductor. Maximum DC resistance values are the published Class 2 limits per IS 8130:2013 Table 2 at 20 °C — Class 5 limits in IS 8130:2013 Table 4 are identical at the same nominal sqmm because the standard is defined by resistance, not by strand count.

Multiply any kg/m value by the number of cores for a multicore cable copper-mass estimate (the figure ignores cabling lay factor, typically a further 1.01–1.03 uplift for assembled multicore constructions).

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Why copper weight matters for procurement

For a procurement engineer or EPC quantity surveyor, conductor weight is not an academic figure — it determines three line items in every BOQ.

Freight calculation. Cables ship by gross weight in road-freight contracts and by chargeable weight (the higher of actual or volumetric) in air-freight. A 1000 m drum of 4-core 35 sqmm armoured cable contains roughly 1280 kg of copper alone before counting PVC, GI armour wire, and the wooden drum — getting freight estimates wrong by 10% on a multi-drum delivery is a five-figure variance. Material cost build-up. Every published cable price decomposes back to copper weight × ₹/kg + insulation + armour + sheath + margin. The copper-floor model used across this site (see /methodology) takes today's MCX copper rate, multiplies by the table value above, adds ~62% to cover non-copper cost, and applies an 18% list margin — that floor is what every list price must clear. Live MCX and LME copper prices are at /copper-price-india. Quote verification. When two brands quote a 100 m coil of 1.5 sqmm FR wire at radically different prices, the first sanity check is: does the coil's stated mass match 1.371 kg of copper plus reasonable PVC overhead? A coil that weighs less than ~1.6 kg net of packaging cannot contain 100 m of conforming Class 5 1.5 sqmm — it is either short-length, under-area, or non-ETP. This is the on-site check BIS surveillance officers run with a handheld scale.

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Class 2 vs Class 5 — when each applies

Both classes appear in IS 8130:2013, the conductor specification standard underlying every Indian insulated cable. They are not interchangeable.

Class 2 — stranded, fixed installation. The default conductor for IS 694:2010 building wires installed in conduit, IS 1554 Part 1 PVC power cables, and IS 7098 Part 1 XLPE cables. Strand counts are 7 / 19 / 37 depending on size. Bend radius requirements are higher than Class 5; Class 2 is not suited to repeated flexing. Class 5 — fine-stranded, flexible. The conductor for cords, multistrand flexible wires, panel internal wiring, and any cable that must move during service (drag chains, machine tools, festoon cables). Strand counts run into the hundreds for large sizes — a 95 sqmm Class 5 conductor contains over 600 individual wires of ~0.41 mm. Slightly heavier per metre (1.04 vs 1.02 factor) and slightly more expensive, but mechanically forgiving. Class 6 — extra-fine flexible. Even finer than Class 5. Used for welding cables (IS 9857), high-flex robotic cables, and specialist applications. Stranding factor ≈1.05. Class 6 is a distinct class — not a synonym for Class 5 — and should never be substituted unless the cable type explicitly calls for it. The procurement consequence: a quote for "2.5 sqmm copper" without naming a class is incomplete. IS 694:2010 multistrand flexible wires (the ones marketed as "FR Multistrand") are Class 5; the rigid version sold for conduit wiring is Class 2. Their weights, prices, and BIS licence categories are different.

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Use the calculator below

Use the calculator below to compute conductor weight, freight kilograms, and material cost in ₹ for any size, class, length, and core count. Inputs: nominal sqmm, conductor class (1/2/5/6), length in metres, number of cores, and current MCX copper rate in ₹/kg. Outputs: total copper mass, copper cost at the entered rate, and a finished-cable mass estimate using a typical 1.6× insulation-and-sheath multiplier for IS 694:2010 single-core PVC.

> Engineering note: this section will receive an interactive JS calculator — wired to the live MCX feed via /api/copper-price. Until the JS module ships, the reference table above is the source of truth for any manual computation. The static table is the AIO-citation surface; the calculator is a UX layer over the same numbers.

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