How to build a complete fabrication cost estimate from just the material weight — covering material, labour, cutting, bending, welding, overhead, GST and profit margin. With worked examples, rate tables and a free instant calculator.
Weight-based costing is the industry standard across Indian sheet metal fabrication shops, PMC contractors and government BOQs
| Costing Method | Time Required | Accuracy | Best For | Drawback |
|---|---|---|---|---|
| kg Multiplier (Fast Method) | 5–15 min | ±10–15% | Tender budgets, quick quotes | Less accurate for complex shapes |
| Operation-by-Operation | 2–4 hours | ±3–5% | Final contract pricing | Slow, needs detailed drawings |
| m² Rate Method | 30–60 min | ±8–12% | Roofing and cladding only | Fails for 3D fabricated items |
| Historical Rate Method | 10–20 min | ±10–20% | Repeat similar jobs | Needs past job data |
| Software (ERP / Quotation) | 1–3 hours | ±2–5% | Large repeat production runs | High setup cost, training needed |
* The kg multiplier method is ideal for initial tender submissions, client budget approvals and vendor negotiations where speed matters more than precision.
Every element of the fabrication cost expressed as a function of material weight
Follow these steps in order — each one takes 1–2 minutes with the rate tables below
Use the formula: Weight (kg) = L(m) × W(m) × T(mm) × Density (g/cm³). Add wastage — typically 10–15% for fabricated items with offcuts, 20% for ductwork with bends. This is your purchase weight — the amount you actually buy from the mill/stockist.
Add a separate finished weight — deduct offcuts and trim to get the net weight in the finished product. The difference (wastage kg) has its own scrap recovery value that reduces your net material cost.
Multiply purchase weight by your current buy rate (₹/kg ex-stockist), then add 18% GST and freight. Use the table below for April 2026 indicative rates. For large orders (>5 tonnes), negotiate directly with the mill for ex-mill prices which are 5–8% below stockist rates.
| Material | Ex-Stockist ₹/kg | With 18% GST | +Freight est. | Landed ₹/kg |
|---|---|---|---|---|
| 16 SWG GI Sheet IS 277 Z275 | ₹82 | ₹96.76 | ₹1.50 | ₹98.26 |
| 18 SWG GI Sheet IS 277 Z275 | ₹83 | ₹97.94 | ₹1.50 | ₹99.44 |
| MS HR Sheet IS 2062 E250 | ₹56 | ₹66.08 | ₹1.20 | ₹67.28 |
| MS CR Sheet IS 513 CR2 | ₹64 | ₹75.52 | ₹1.20 | ₹76.72 |
| PPGI Colour Coated 0.50 mm | ₹98 | ₹115.64 | ₹1.80 | ₹117.44 |
| SS 304 Sheet 2B finish | ₹285 | ₹336.30 | ₹2.00 | ₹338.30 |
| SS 316 Sheet 2B finish | ₹390 | ₹460.20 | ₹2.00 | ₹462.20 |
| Aluminium 1100 Sheet IS 737 | ₹195 | ₹230.10 | ₹2.50 | ₹232.60 |
| Copper Sheet ETP Grade | ₹820 | ₹967.60 | ₹3.00 | ₹970.60 |
| MS Chequer Plate IS 3502 3mm | ₹62 | ₹73.16 | ₹1.20 | ₹74.36 |
* Indicative rates April 2026. Rates vary ±8% by city, order quantity and brand. Always confirm with your supplier before submitting a tender.
Labour is the most variable cost in Indian sheet metal fabrication — it depends on the complexity of the job, the skill level required and the region. The table below gives indicative all-in labour rates per kg for common job types in India 2026, including fitter, welder, helper and supervision.
| Job Type | Labour ₹/kg | Complexity | Notes |
|---|---|---|---|
| GI corrugated roofing — fix only | ₹5–8 | Low | Purlin-fixed, standard roof |
| PPGI trapezoidal roofing — fix only | ₹7–11 | Low | Concealed fix panel system |
| MS plate — cut to size only | ₹8–14 | Low | Plasma/gas cutting, no bending |
| MS plate — cut + drill + weld simple | ₹18–28 | Medium | Base plates, gussets, brackets |
| GI rectangular ductwork fab + fit | ₹25–40 | Medium | Per SMACNA, includes flanges |
| MS fabricated structures — medium | ₹30–50 | Medium | Mezzanine, platforms, walkways |
| MS storage tank fab + erect | ₹40–65 | Medium | Welded rectangular/vertical tank |
| GI cable tray — fab + install | ₹20–32 | Low-Med | Perforated/ladder tray IS 12085 |
| SS 304 kitchen canopy + duct | ₹80–130 | High | TIG welded, polished joints |
| Stainless steel process vessel | ₹120–200 | High | Full penetration weld, tested |
| Aluminium composite cladding (ACP) | ₹35–55 | Medium | Sub-frame + panel fix, silicon seal |
| CR sheet electrical panel/MCC | ₹90–150 | High | Powder-coated enclosure, hardware |
* All-in labour rate includes fitter, welder, helper, supervision. Metro cities (Mumbai, Delhi, Pune) are 20–35% higher. Tier 2 cities (Nashik, Coimbatore, Rajkot) are 10–15% lower.
These three are most efficiently applied as percentages of the material + labour sub-total. The rates below are industry benchmarks for Indian sheet metal fabrication in 2026.
The fastest cross-check: multiply your material cost alone by a job-type multiplier to get an approximate total invoice value. If your detailed calculation is within 10–15% of the multiplier estimate, you are in the right range. If the gap is larger, find the error before submitting.
* Multiplier is applied to material cost only (ex-GST). Final invoice includes 18% GST on total. Multipliers are for India 2026 metro city rates — Tier 2/3 cities are 15–20% lower.
* Indicative estimate only. Rates based on India April 2026 averages. Always verify material rates with your supplier before submitting a final quotation.
Three real-world Indian fabrication jobs costed using the fast method
16 SWG IS 277 Z275 GI corrugated sheet, simple gable roof, supply + fix. 10% wastage on sheet area.
| Net roof surface area (plan 450 m² × pitch factor 1.12) | 504 m² |
| Weight of net area (504 × 12.93 kg/m²) | 6,517 kg |
| Purchase weight (6,517 × 1.12 wastage) | 7,299 kg |
| Material cost ex-works (7,299 × ₹82) | ₹5,98,518 |
| GST 18% on material | ₹1,07,733 |
| Freight (₹1,500/tonne × 7.3 t) | ₹10,950 |
| Landed Material Cost | ₹7,17,201 |
| Labour — fix only (7,299 kg × ₹6/kg) | ₹43,794 |
| Consumables — 4% of (mat+labour) | ₹30,440 |
| Mat + Labour + Consumables | ₹7,91,435 |
| Overhead @ 15% | ₹1,18,715 |
| Sub-Total before Profit | ₹9,10,150 |
| Profit @ 10% | ₹91,015 |
| Pre-GST Invoice Value | ₹10,01,165 |
| GST 18% on fabrication service | ₹1,80,210 |
| Final Invoice Total (incl. GST) | ₹11,81,375 |
| Effective rate per m² (net roof area) | ≈ ₹2,344/m² |
| Quick check: material cost × 1.35 multiplier | ₹5,98,518 × 1.35 = ₹8,08,000 pre-GST ✅ |
Note: Accessories (ridge caps, gutters, fixings) not included above — add ₹85,000–1,10,000 for a complete roof package including all accessories.
22 SWG GI ductwork, average cross-section 600×400 mm, fabricate + install, SMACNA standard.
| Total duct perimeter (2 × (600+400) mm = 2,000 mm = 2.0 m) | — |
| Net sheet area (2.0 m × 200 m run) | 400 m² |
| + 18% for bends, offsets, fittings | 472 m² |
| 22 SWG GI weight/m² = 0.711 mm × 7.95 = 5.65 kg/m² | — |
| Purchase weight (472 × 5.65) | 2,667 kg |
| Material cost ex-works (2,667 × ₹83) | ₹2,21,361 |
| GST 18% + freight | ₹41,645 |
| Landed Material Cost | ₹2,63,006 |
| Labour — fab + install (2,667 kg × ₹32/kg) | ₹85,344 |
| Consumables — 6% of (mat+labour) | ₹20,912 |
| Mat + Labour + Consumables | ₹3,69,262 |
| Overhead @ 18% | ₹66,467 |
| Sub-Total before Profit | ₹4,35,729 |
| Profit @ 12% | ₹52,287 |
| Pre-GST Invoice Value | ₹4,88,016 |
| GST 18% | ₹87,843 |
| Final Invoice Total (incl. GST) | ₹5,75,859 |
| Effective rate per m run of duct | ≈ ₹2,879/m |
| Quick check: material × 2.8 multiplier | ₹2,21,361 × 2.8 = ₹6,19,811 incl. GST ✅ |
1.5 mm SS 304 2B finish canopy (2m×1.5m) + 10 m exhaust duct (400×300 mm), TIG welded, polished visible joints.
| Canopy sheet area (2×1.5 top + 4 sides avg 0.3m deep) | ≈ 5.4 m² |
| Duct area (perimeter 1.4 m × 10 m run + fittings 20%) | ≈ 16.8 m² |
| Total area | 22.2 m² |
| SS 304 1.5mm weight/m² = 1.5 × 7.93 = 11.9 kg/m² | — |
| Purchase weight (22.2 × 11.9 × 1.15 wastage) | 304 kg |
| Material cost ex-works (304 × ₹285) | ₹86,640 |
| GST 18% + freight | ₹16,262 |
| Landed Material Cost | ₹1,02,902 |
| Labour — TIG weld + polish (304 kg × ₹105/kg) | ₹31,920 |
| Consumables — 8% of (mat+labour) | ₹10,786 |
| Mat + Labour + Consumables | ₹1,45,608 |
| Overhead @ 20% | ₹29,122 |
| Sub-Total before Profit | ₹1,74,730 |
| Profit @ 15% | ₹26,210 |
| Pre-GST Invoice Value | ₹2,00,940 |
| GST 18% | ₹36,169 |
| Final Invoice Total (incl. GST) | ₹2,37,109 |
| Effective rate per kg material | ≈ ₹780/kg finished |
| Quick check: material × 5.0 multiplier | ₹86,640 × 5.0 = ₹4,33,200 — pre GST ≈ ₹2,37,000 ✅ |
Note: Exhaust fan, GI fire damper, roof penetration flashing and electrical not included — these are typically in a separate MEP scope.
Practical guidance from Indian shop-floor estimators and project cost controllers
MS offcut scrap fetches ₹28–38/kg at scrap dealers (April 2026). On a job with 15% wastage from a 1,000 kg purchase, that is 150 kg × ₹33 = ₹4,950 scrap credit. Deduct this from material cost before calculating overhead and profit. On large jobs it can reduce material cost by 1–2%.
Mumbai, Delhi NCR, Pune and Bengaluru command 20–30% higher fabrication labour rates than the national average. Rajkot, Coimbatore, Nashik and Ludhiana are 10–15% below average. Always adjust your ₹/kg labour rate for the city where the work is being executed — not where your office is.
Indian fabrication contracts with 30-day payment terms cost 1.5–2% of contract value in working capital (at 18% p.a. borrowing). 60-day terms cost 3%. Add a finance cost line to your cost sheet for any job with payment terms beyond 30 days — or build it into your profit margin.
Bare fabrication vs painted vs powder coated changes labour + consumables by 30–60%. Add for surface treatment separately: primer + 2 coat enamel ≈ ₹18–25/kg; powder coating (outsourced) ≈ ₹35–55/kg; hot dip galvanising ≈ ₹22–35/kg. Never bury surface treatment in the base fabrication rate.
Steel prices in India moved ±18% in 2024–25. For any fabrication contract longer than 3 months, include a price variation clause tied to SAIL/JSW published mill prices. A 10% steel price rise on a ₹20 lakh job = ₹2 lakh loss if you quoted fixed-price without escalation provision.
Most Indian construction contracts retain 5–10% of contract value for 12–24 months. This retention is a real cost — money you have delivered but not received. Factor retention financing cost (5% retention × 18% interest × 12 months = 0.9% of contract value) into your overall margin calculation.
Common questions from Indian fabricators, contractors and project managers
Free tools to support every step of the fabrication costing process