Understanding Welding Cost Estimation: A Practical Guide

Estimating welding costs is an essential skill for fabricators, estimators, and project managers alike. A well-structured estimate supports profitability, efficient resource use, and competitive bidding.

This guide walks you through the main cost elements, a practical step-by-step procedure, and includes key formulas, symbols, and worked examples with final numbers so you can see exactly how it all fits together. An article version can be found here.

Why Welding Cost Estimation Matters

If you don’t know your real welding cost per weld length, you risk:

• Underquoting and losing money

• Overquoting and losing bids

• Missing hidden costs like power and real labour overhead

The Four Main Costs

Every weld cost breaks down into:

1. Labour (wages + benefits + shop overhead)

2. Power (electricity used by the welding machine)

3. Consumables (electrodes, filler wire, shielding gas)

4. (Base Material — not covered here, but consider it for full jobs)

In simple terms:

Total Welding Cost = Labour Costs + Consumable Costs + Power Costs + Base Material Costs

How to Build a Realistic Labour Rate

A welder’s shop cost is not just the hourly wage.

Example:

• Hourly wage: $35/hr

• Employer-paid payroll costs (CPP/EI/WSIB): $4/hr

• Vacation pay (4%): $1.40/hr

• Health & dental benefits: $3/hr

• Shop overhead (heat, lights, supervision, admin): $12/hr

Total: $55–$60/hr real cost

Use your actual numbers — your accountant or payroll team can help.

Key Concept: Operating Factor

Welders aren’t welding 100% of the time.

• Typical Arc-On time: 20–40%

• The rest is setup, moving parts, waiting, or repositioning.

This ratio is called the Operating Factor (OF):

OF = (Arc Time / Total Shift Time)

A higher OF means better use of labour and equipment.

How to Get Good Numbers

• Deposition rate → Get from your welding procedure spec (WPS) or electrode datasheet. (E.g., SMAW: 6–10 lb/hr)

• Machine power draw → Use typical amps × volts, then adjust for efficiency.

• Hydro rate → Check your latest BC Hydro bill (e.g., $0.1408/kWh).

Worked Example # 1

Scenario: You’re welding a fillet-joint using a Lincoln CRX10ia Cobot Welder, RapidArc ArMix GMAW process using R450 PowerWave.

Fillet Joint

Key data:

• Wire Feed Speed 𝐷 = 200𝑖𝑛.𝑚𝑖𝑛−1

• Travel Speed 𝐷 = 18𝑖𝑛.𝑚𝑖𝑛−1

• Deposition efficiency 𝜂𝑑 = 0.96

• Wire (ER70S-6) Cost 𝐶𝑤𝑖𝑟𝑒 = $3.64 𝑙𝑏−1

• Wire linear density 𝜆 = 2200𝑖𝑛.𝑙𝑏−1

• Labour rate (incl. overhead) 𝐶hr = $39.20 ℎ−1

• Operating factor OF ≈ 0.30

• Gas Flowrate 55𝑓𝑡3.ℎ𝑟−1

• Gas Cost 𝐶𝑔𝑎𝑠 = 4.73$.𝑓𝑡−3

• Arc voltage ≈ 21.4 V (from PowerWave R450 readings)

• Amperage ≈ 157 A (from PowerWave R450 readings)

• Weld Length 𝐿 = 5.11𝑖𝑛 (measured after welding-can also just

  be length of piece)

• BC Hydro rate: $0.1408/kWh

• Power efficiency ≈ 0.85

• Power factor ≈ 0.8

• Updated labour cost: $39.20/hr (incl. vacation, benefits)

Fillet Joint Scan Before and After Weld

Step 1: Calculate Weld Area

To calculate the weld area, we typically start with either the specified fillet size or the actual weld geometry. In most workshop settings, inspectors or welders use simple measurement tools, or they estimate the area based on the target fillet size.

For our example, we’ll refer to the dimensions shown in Figure above. Since fillet welds form roughly triangular cross-sections, we can approximate the weld area as that of a right triangle. However, to account for over-welding—which is common in practice—we add an additional 15% to the calculated area.

Note: 5 mm ≈ 0.2 in.

Equation for Weld Area

A_w (Weld Cross-sectional Area) = A_triangle + A_overfill

A_w = A_triangle×(1+0.15) = (1/2 × 0.2 × 0.2)×(1+ 0.15)

A_w = 0.02 + 0.003 = 0.023 in²

Note: You can use SKC weld area calculator to save time.

Step 2: Volume and Weight

To estimate the weight of the deposited weld metal, we begin by calculating its volume. This is done by multiplying the cross-sectional area of the weld by the length of the weld bead. Once we have the volume, we multiply it by the density of the filler metal to determine the total weight.

Equation for Volume
The volume of weld metal deposited is given by:

V = A_w × L = 0.023 in² × 5.11 in = 0.11753 in³

Equation for Weight

Multiplying the volume by the density gives us the weight:

W = V × ρ = 0.11753 in³ × 0.283 lb/in³ = 0.0333 lb

Parameter Definitions

• A_w: Cross-sectional area of the weld bead (in²)

• L: Length of the weld (in)

• V: Volume of weld metal deposited (in³)

• ρ: Density of the filler metal (lb/in³), typically 0.283 for steel

• W: Weight of deposited weld metal (lb)

Step 3: Estimating Arc Time

Arc time is the amount of time the welding arc remains active. This is important for calculating labor, power consumption, and overall process efficiency.

Step 3.1 – Calculate Weight of Wire Consumed

The weight of consumed wire depends on how much of it is actually deposited during welding. This is where the deposition efficiency comes in:

W_wire = W_weld / η_d = 0.0333 lb / 0.96 = 0.03197 lb

Where:

• W_weld = Weight of deposited weld metal (lb), from Step 2
• η_d = Deposition efficiency (typically 0.96 for GMAW)

Step 3.2 – Calculate Length of Consumed Wire

The length of wire consumed is calculated using the linear density of the wire and the weight of wire consumed:

L_wc = λ_wire × W_wire = 2200 in/lb × 0.03197 lb = 70.33 in

Where:

• λ_wire = Linear density of the filler wire (in/lb)
• W_wire = Weight of wire consumed (lb)

Step 3.3 – Calculate Arc Time from Wire Consumption

Arc time can be determined by dividing the length of welding wire consumed by the wire feed speed:

T_arc = L_wc / WFS = 70.33 in / 200 in/min = 0.352 min ≈ 21.1 s

Where:

• T_arc = Arc time (minutes or seconds)

• L_wc = Length of wire consumed (inches)

• WFS = Wire Feed Speed (in/min)

Step 4: Estimating Weld Consumables

In this step, we account for two primary consumables in the welding process: filler wire and shielding gas.

The weight of wire consumed (W_wire) was already calculated in Step 3:

W_wire = 0.03197 lb

Now, we calculate the volume of shielding gas used during welding. This depends on the arc time and the gas flow rate.

Shielding Gas Consumption

The formula for shielding gas consumption is:

G_c = (T_arc × G_flow) / 60
G_c = (0.352 min × 55 ft³/hr) / 60 = 0.323 ft³

Where:

• G_c = Total shielding gas consumed (ft³)
• T_arc = Arc time in minutes (from Step 3)
• G_flow = Gas flow rate in ft³/hr

This gives us an estimate of how much shielding gas (typically Argon or a gas mix) is used during the weld. While the amount may seem small for a short weld, it adds up over longer production runs and should be included in cost estimates.

Step 5: Estimating Power Cost

Power cost is a small but important part of the total welding cost. It’s based on the electrical energy consumed during the weld, which depends on the arc power, equipment efficiency, power factor, and arc time.

Step 5.1 – Calculate Arc Power

P_arc = V × I = 21.4 V × 157 A = 3.36 kW Where:

• V = Arc voltage (volts)
• I = Arc current (amperes)
• P_arc = Power delivered to the arc (kW)

Step 5.2 – Adjust for System Efficiency

P_input = P_arc / η_eff = 3.36 kW / 0.85 = 3.91 kW

Where:

• η_eff = System efficiency (dimensionless)
• P_input = Power drawn by the welding machine (kW)

Step 5.3 – Account for Power Factor

P_real = P_input × PF = 3.91 kW × 0.8 = 3.128 kW

Where:

• PF = Power factor (dimensionless)
• P_real = Actual power drawn from the grid (kW)

Step 5.4 – Calculate Energy Used

Arc time from Step 3 is 0.352 min, or 0.00587 hr:

E_kWh = P_real × t = 3.128 kW × (0.352 / 60) hr = 0.01835 kWh

Step 5.5 – Compute Power Cost

Power Cost = E_kWh × C_kWh = 0.01835 kWh × $0.1408/kWh = $0.0026

Even though the power cost is quite low—just a fraction of a cent—this estimate only includes the energy consumed during welding. Additional power usage by robots, controls, and idle systems is not accounted for here, meaning the actual cost could be slightly higher in real-world scenarios.

Step 6: Final Cost Breakdown

To determine the total welding cost, we sum the three key components:

1. Labour Cost

2. Consumables Cost

3. Power Cost

Labour Cost

Labour cost is based on the arc time and hourly labour rate:

Labour = T_arc × C_hr = (0.352 / 60) hr × $39.20/hr = $0.229

Where:

• T_arc = Arc time in minutes
• C_hr = Labour rate ($/hr)

Consumables Cost

This includes the cost of shielding gas and filler wire:

Consumables = G_c × C_g + W_wire × C_wire
= 0.323 ft³ × $4.73/ft³ + 0.03197 lb × $3.64/lb
= $1.644

Where:

• G_c = Volume of shielding gas consumed (ft³)
• C_g = Cost per cubic foot of gas
• W_wire = Weight of welding wire used (lb)
• C_wire = Cost per pound of wire

Power Cost

Previously calculated in Step 5:

Power = $0.0026

Total Welding Cost

Summing all components:

Total Cost = $0.229 (Labour) + $1.644 (Consumables) + $0.0026 (Power) = $1.8756

This final cost represents the direct welding cost for this short segment. It’s ideal for budgeting, quoting, and evaluating efficiency in a production setting.

Worked Example # 2

Scenario: You’re welding a flange on a beam-column connection as shown in the figure below.

Image Source: The Procedure Handbook of Arc Welding, Estimating Welding Costs

Key data:

• Plate thickness: 1 ¾ in

• Bevel angle: 45°

• Root spacing: ¼ in

• Reinforcement: ⅜ in (per AWS limit)

• Electrode: E7027, 3/16 in, 280 A (AC)

• Deposition rate: 7.8 lb/hr

• Deposition efficiency: 66%

• Electrode price: $0.35/lb

• Updated labour cost: $39.20/hr (incl. vacation, benefits)

• Operating Factor: 0.30

• Power source: Lincoln R450 Power Wave

• Welding voltage: ~32 V

• Power factor: 0.8

• Hydro rate: $0.1408/kWh

• Weld length: 14 in

• Weld metal density: 0.283 lb/in³

Step 1: Calculate Weld Area

The weld Area can be calculated by splitting the area in figure 1 into 3 sections, “Area 1” is obtained using formula for rectangle, “Area 2” is obtained using formula for triangle, and “Area 3” is obtained using formula for parabola.

A_w (Weld Cross-sectional area) = Area₁ + Area₂ + Area₃

A_w = rt + (t² / 2) + (2 / 3) a (r + t)

A_w = (0.25 × 1.75) + (1.75² / 2) + (2 / 3) × 0.375 × (0.25 + 1.75) = 2.47 in²

Step 2: Calculate Volume, then Weight of Weld

V (Volume of Weld) = A_w (Weld Cross-sectional area) × L (Length of weld)

V = A_w × L = 2.47 in² × 14 in = 34.6 in³

W (Weight of Weld) = V (Volume of Weld) * ρ(density of weld metal)

W = V × ρ = 34.6 in³ × 0.283 lb/in³ = 9.62 lb

Step 3: Arc-Time Requirement

T_arc (Arc Time) = Weight of Weld / (D (Deposition rate) × OF (Operating Factor) )

T_arc = W / (D × OF) = 9.62 / (7.8 × 0.30) = 4.11 hr

Step 4: Electrode Consumption

W_e (Weight of Electrode Consumed) = W(Weight of Weld metal) / η_d (deposition efficiency)

W_e = W / η_d = 9.62 / 0.66 = 14.6 lb

Step 5: Power Costs

P_arc (Arc Power) = V (Welding Voltage) × A (Welding Amperage)

P_arc = 32 V × 280 A = 8.96 kW

P_input (Input Power) = P_arc (Arc Power) / Machine Efficiency

P_input = 8.96 / 0.85 = 10.54 kW

P_real = P_input (Input Power) × Power Factor

P_real = 10.54 kW × 0.8 = 8.43 kW

E_kWh (Total Power consumed) = P_real (Consumed Power) × ArcTime

E_kWh = 8.43 kW × 4.11 hr = 34.65 kWh

Power Cost = E_kWh (Total Power consumed) x BC-Hydro Power Cost

Power Cost = 34.65 kWh × $0.1408/kWh = $4.88

Final Costs:

Labour Cost = 4.11 hr × $39.20/hr = $161.31

Electrode Cost = 14.6 lb × $0.35/lb = $5.11

Power Cost = $4.88

Total Welding Cost = $161.31 + $5.11 + $4.88 = $171.30

Final Key Points

• Use real wage + benefits + overhead.

• Include realistic arc time — most shops are ~30% efficient for manual work.

• Don’t forget power, even for small jobs.

• Use SKC weld area calculator if needed.