Welding Cost Calculator

Welding cost is made up of three main components — filler metal, labour and machine time, and shielding gas or other consumables — plus an overhead margin to cover shop costs not tied to any single job. Getting a realistic total means treating each component correctly rather than just multiplying weld length by a flat rate per metre, because filler cost and labour cost scale very differently.

Filler metal cost is straightforward: the total filler weight used (weld length times a consumption rate in kg per metre, which depends on joint size, weld type, and process) multiplied by the cost per kilogram of that filler.

Labour and machine cost is where the biggest estimating error usually happens. Welding speed (how fast the arc travels along the joint, in cm/min) only tells you the arc-on time — the time the welder is actually welding. In real shop conditions, a welder is not welding continuously; time is spent on setup, repositioning, changing electrodes, cleaning slag, and fit-up checks. This is captured by the arc-on (duty) factor — the fraction of total working time actually spent welding, typically 20–40% for manual stick or TIG welding and higher for mechanised or robotic welding. Total time is the arc-on time divided by this duty factor, and that total time — not just the arc-on time — is what the labour and machine rate should be applied against.

Total Time = Arc-On Time ÷ Duty Factor

Gas and consumables (shielding gas, tungsten electrodes, nozzles, grinding discs) are usually estimated as a cost per metre of weld based on shop experience, since they don't scale as cleanly with filler weight as the filler cost itself does.

Adding these three together gives the subtotal direct cost, and an overhead percentage on top accounts for indirect shop costs — equipment depreciation, power, general supervision — that aren't tied to any one weld but still need to be recovered across all jobs.

1. Costing labour on arc-on time alone. Welding speed only measures the time the arc is actually running; ignoring the duty factor and costing labour on arc-on time alone can understate the true labour cost by half or more.

2. Using an unrealistic duty factor. A duty factor that's too optimistic (assuming continuous welding) badly underestimates cost, while too conservative a figure overestimates it — base this on actual shop time studies for the specific job type rather than a generic guess.

3. Forgetting filler losses (spatter, stub ends, grinding). Actual filler consumption is usually somewhat higher than the theoretical weld-metal volume alone, due to spatter loss, stick-electrode stub ends left unused, and deposition efficiency below 100% — use a consumption rate based on real shop data, not just theoretical bead volume.

4. Ignoring joint preparation and fit-up time. Bevelling, cleaning, tacking and fit-up checks are real time costs that happen before the arc is even struck — for jobs with heavy preparation, this can be a bigger cost driver than the welding itself and needs its own separate estimate.

5. Applying one cost-per-metre rate across very different joint sizes. A thick multi-pass weld and a thin single-pass weld have very different filler and time requirements per metre — a single blanket rate across a job with mixed joint sizes will misprice the smaller and larger welds in opposite directions.

6. Skipping the overhead margin. Direct costs (filler, labour, gas) don't cover indirect shop costs like equipment depreciation, power, and supervision — quoting a job at direct cost alone erodes the margin needed to keep the shop running.