Welding cost per metre (labour, wire, gas and power)

t_{a} = \frac{m_{L}}{D_{R}}

C_{L} = \frac{R t_{a}}{O_{F} / 100}

C_{F} = \frac{m_{L}}{η / 100} P_{w}

C_{G} = \frac{60 Q_{g} t_{a}}{1000} P_{g} + \frac{U I t_{a}}{1000} P_{e}

C = C_{L} + C_{F} + C_{G}

where
$t_{a}$: arc-on time per metre (h)
$m_{L}$: weld metal per metre (kg/m)
$D_{R}$: deposition rate (kg/h)
$C_{L}$: labour and overhead cost (£/m)
$R$: labour and overhead rate (£/h)
$O_{F}$: operating factor (%)
$C_{F}$: filler cost (£/m)
$η$: deposition efficiency (%)
$P_{w}$: wire or electrode price (£/kg)
$C_{G}$: gas and power cost (£/m)
$Q_{g}$: gas flow rate (l/min)
$P_{g}$: gas price (£/m³)
$U$: arc voltage (V)
$I$: welding current (A)
$P_{e}$: electricity price (£/kWh)
$C$: total welding cost (£/m)

Explain this equation

Builds up the cost of a metre of weld from labour, filler, gas and electricity. Use it to price fabrication or compare processes.

Arc time per metre is the weld metal divided by the deposition rate. Labour is charged for all paid time, so arc time is divided by the operating factor before multiplying by the rate. Filler bought is the deposit divided by the efficiency, times its price. Gas is flow × 60 × hours in litres, divided by 1000 for m³, times price. Power is volts × amps × hours in watt-hours, divided by 1000 for kWh, times price.

Each cost is a quantity times a unit price; they add to the total.

Sense check: 0.25 kg/m at 3 kg/h is 5 minutes of arc per metre; at £45/h and 40% that is about £9.40 of labour, against under £1 each for wire and for gas and power.

Watch out: labour dominates. Improving the operating factor or deposition rate saves far more than cheaper wire.

Builds up the cost of a metre of weld from labour time, filler, gas and electricity, using the cost-per-weight-of-weld-metal method.

Enter your values to see the result.

Good to know

Labour is nearly always the largest part, so oversize welds and a low operating factor cost far more than the wire. Power here is arc power only (U × I); the machine draws more from the supply, typically 10–20 % on an inverter, so treat it as a minimum. Use the fillet or butt weld calculator for weld metal per metre.

Common mistake

Leaving out overheads (premises, insurance, equipment, consumable parts) from the hourly rate, which makes welding look cheaper than it is.

Limits

Excludes preparation, fit-up, grinding, inspection, flux (SAW) and contact tips/nozzles unless they are built into the hourly rate.

Sources

Results are calculations from the published methods and figures shown, and depend on the data you enter. Follow the welding procedure specification (WPS), BS EN ISO 15614/9606, BS EN 1090, BS EN 1993 and manufacturers’ data. Structural welds need qualified welders and engineered designs.

Welding cost per metre (labour, wire, gas and power)

Good to know

Common mistake

Limits

Sources

Welding cost per metre (labour, wire, gas and power)

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