Estimate weld metal volume and weight from joint geometry, then convert that into a purchasing quantity using process deposition efficiency and a waste allowance.
V = a²/2 × L
Package size is per spool, box, or rod bundle, in the weight unit selected above. Leave blank to skip the package-count estimate.
Deposition efficiency accounts for material lost to spatter, stub loss, slag, and fume, not just process differences; actual shop efficiency varies with technique, joint access, and equipment condition. Track your own historical consumption where possible and adjust the value here to match.
Joint geometry gives the weld metal volume, density turns it into weight, and deposition efficiency turns that weight into what you actually need to buy.
| Process | Efficiency | Where the rest goes |
|---|---|---|
| GTAW | ~100% | Essentially no loss |
| GMAW (solid wire) | ~95% | Spatter |
| SAW | ~95% | Flux is bought separately |
| FCAW | ~85% | Slag, spatter |
| SMAW | ~65% | Stub ends, coating, slag |
Use your own consumption records when you have them.
The calculation assumes an ideal flat-faced fillet. Convex profiles, oversized legs, and root gaps all add metal. Volume grows with the square of leg size, so a 1/4 in fillet welded at 5/16 in uses about 56% more weld metal.
Combine this with the Welding Production & Cost Estimator for arc time and total job cost, or get in touch for a procedure- and program-specific take-off.