To calculate MIG welding cost per metre, first define the weld geometry. Then add wire, gas, power, productive labour, equipment and job-specific costs. Divide by accepted weld length—not by an optimistic robot travel distance.
For an Indian fabrication quote, rupees are the easy part. The difficult questions are whether the drawing specifies leg length or throat thickness, how much of the shift is actually spent welding, and who pays for setup and rework. This guide provides a reproducible costing method. Every rupee amount below is a hypothetical input, not a surveyed Indian market price, supplier quotation or promised saving.
Start with the drawing, not the hourly rate
Record the material, joint, weld size, length, position, pass count and inspection requirement. For an ideal equal-leg fillet, triangular cross-sectional area is half the square of the leg length. TWI’s weld-volume guide explains this geometry and the need to consider additional weld metal. Leg length and throat thickness are different dimensions; confusing them changes the estimate substantially.
Ideal equal-leg steel fillet: 5 mm leg, 1 metre long
Area = 0.5 x 5^2 = 12.5 mm2
Volume = 12.5 x 1,000 = 12,500 mm3 = 0.0000125 m3
Assumed steel density = 7,850 kg/m3
Deposited mass = 0.0000125 x 7,850 = 0.098125 kg/m
At an assumed 95% deposition efficiency:
Purchased wire = 0.098125 / 0.95 = 0.103289 kg/m
At an assumed travel speed of 18 m per arc-hour:
Required deposited mass rate = 0.098125 x 18
= 1.76625 kg per arc-hourThis is a geometric model, not a welding procedure. It excludes reinforcement, gaps, penetration contributions and starts or stops. Use the actual weld profile and qualified process requirements for production. Deposition efficiency converts wire consumed into metal deposited; it is not the same as the fraction of a shift spent welding.
Check mass before pricing different weld sizes
| Fillet leg | Ideal area | Deposited steel per metre | Wire per metre at assumed 95% efficiency |
|---|---|---|---|
| 4 mm | 8 mm² | 0.06280 kg | 0.06611 kg |
| 5 mm | 12.5 mm² | 0.09813 kg | 0.10329 kg |
| 6 mm | 18 mm² | 0.14130 kg | 0.14874 kg |
| 8 mm | 32 mm² | 0.25120 kg | 0.26442 kg |
Going from a 5 mm to a 6 mm leg increases ideal area by 44%, because 36 divided by 25 is 1.44. A 6 mm fillet has 2.25 times the area of a 4 mm fillet. That does not mean total job cost always changes by the same ratio: setup, travel speed, pass count and inspection can change too. Never reduce a specified weld size to save cost without engineering approval.
Worked manual-versus-robotic cost model
The comparison deliberately uses identical ideal geometry and arc travel speed for both methods. It changes the assumed operating factor and allocated hourly costs. The rates are invented modelling inputs so you can replace them with invoices and time studies. The electrical input is also assumed; no current or voltage recipe is prescribed.
Shared hypothetical inputs
Wire Rs 110/kg
Shielding gas Rs 350/m3, flow 14 L/min
Electrical input 7.6 kW during welding, Rs 8/kWh
Consumable allocation Rs 3 per welded metre
Arc travel speed 18 m/hour
Shared cost per welded metre
Wire: 0.103289 x 110 = Rs 11.36
Gas: (14 x 60 / 1,000) / 18 x 350 = Rs 16.33
Power: 7.6 x 8 / 18 = Rs 3.38
Consumables = Rs 3.00
Shared total, using unrounded inputs = Rs 34.07
Manual assumptions
Loaded labour: Rs 450 per scheduled hour
Arc-on fraction: 40%; effective output = 18 x 0.40 = 7.2 m/h
Machine: Rs 150,000 / 5 years / 2,000 scheduled h/year
= Rs 15 per scheduled hour
Labour/m = 450 / 7.2 = Rs 62.50
Equipment/m = 15 / 7.2 = Rs 2.08
Subtotal = Rs 98.66/m
With assumed 10% overhead = Rs 108.52/m
Robot assumptions
Allocated labour: Rs 250 per scheduled hour
Arc-on fraction: 70%; effective output = 18 x 0.70 = 12.6 m/h
Cell: Rs 4,500,000 / 8 years / 5,000 scheduled h/year
= Rs 112.50 per scheduled hour
Labour/m = 250 / 12.6 = Rs 19.84
Equipment/m = 112.50 / 12.6 = Rs 8.93
Subtotal = Rs 62.84/m
With assumed 10% overhead = Rs 69.13/m
Difference: Rs 39.39/m, or 36.30%, in this model only.
All capital calculations assume zero residual value.The annual hours above are scheduled operating hours, not arc hours. The operating factor is applied once when converting to metres. If your equipment rate is already calculated per arc-hour, dividing by the operating factor again double-counts the allowance. Robot controller and idle power, fixture costs, maintenance, financing, setup, inspection and repairs are not separately priced in this simplified comparison; add measured amounts rather than assuming the 10% allocation covers them.
Turn welded metres into accepted metres
A metre that fails inspection is not saleable output. For a batch, total accepted-metre cost is the complete batch cost divided by accepted length. Include repair labour, repeat inspection, scrap and the time tied up in rework. Do not merely divide by first-pass yield when repairs have different costs and some parts remain recoverable.
Separate hypothetical batch example
Initial welding and handling cost = Rs 10,000
Setup and inspection = Rs 2,000
Repair and repeat inspection = Rs 1,000
Final accepted length = 100 m
Accepted-metre cost = (10,000 + 2,000 + 1,000) / 100
= Rs 130/m
If only 90 m is finally accepted at the same total cost:
Accepted-metre cost = 13,000 / 90 = Rs 144.44/mLog welding, fitting, loading, tip changes, inspection and repair separately during a representative trial. This makes the estimate useful: you can see whether a fixture, a positioner, better fit-up or a change in scheduling would address the actual bottleneck.
What to add before issuing a quotation
- Setup and programming: allocate them over the committed batch, not a hoped-for future order.
- Fixture amortisation: state who owns the fixture and pays for revisions.
- Gas losses and idle consumption: use purchased volume and measured practice where possible.
- Consumables and maintenance: avoid counting tips or repairs both in a loaded hourly rate and a separate per-metre line.
- Acceptance and documentation: include the required inspection, traceability and customer records.
- Commercial terms: define tax treatment, transport, payment period, quantity changes and quote validity.
- Margin: keep profit separate from cost. A 20% markup on cost is not a 20% margin on the selling price.
Ask suppliers quoting “per metre” to state the weld size, passes, material, position, fit-up assumptions and inspection scope. Two rates are not comparable if one includes fixtures and accepted parts while the other covers arc time alone. Treat a low quote as a scope question before treating it as a bargain.
When a robot changes the economics
A robot can improve repeatability of motion and increase productive arc time, but the business case depends on repeatable joints, fit-up, suitable fixtures and enough loaded work. High product variety or frequent changes can consume the apparent saving in setup. Run your model at conservative and expected utilisation, and include an accepted-quality trial before purchase.
Continue with robot hourly-cost modelling, welding fixture design, robot welding cell cost and acceptance testing. Those are separate decisions from the material-and-time calculation on this page.
How much does a metre of MIG weld cost in India?
There is no reliable single rate without the joint and scope. Our hypothetical 5 mm fillet model gives Rs 108.52 manually and Rs 69.13 robotically before separately priced job-specific costs. These are calculations, not market quotations.
How much metal is in a 5 mm fillet weld?
An ideal equal-leg 5 mm steel fillet has area 12.5 mm² and about 0.098125 kg per metre at assumed density 7,850 kg/m³. Real geometry and process allowances may change this.
Does a robot always use less wire?
No. The required deposited metal follows the joint geometry. Wire consumption also depends on deposition efficiency, actual weld profile and losses, not simply whether a robot carries the torch.
What is the difference between operating factor and deposition efficiency?
Operating factor is the proportion of scheduled time spent welding. Deposition efficiency is the fraction of consumed filler retained as deposited metal. They affect different parts of the model.
Should I quote welded metres or accepted metres?
Define the contract explicitly. Accepted-metre costing exposes inspection, repair and scrap costs; a rate for arc travel alone can leave those costs unpriced.
Sources and further reading
- TWI: Calculating weld volume and weight — weld geometry, volume and mass; supports the geometric method, not the illustrative Indian-currency inputs.
- TWI: Welding costs, continued — deposition and welding-time concepts.
- TWI: Welding costs — additional costing background.
Method note: all prices, operating factors and capital lives are explicit hypothetical assumptions. The equations have been recalculated; no production trial or supplier price survey is claimed. The featured image is AI-generated, not a weld qualification record.
