Free Welding Calculator

Weld Volume Calculator — Fillet Weld Area, Volume & Filler Metal Weight

Calculate filler metal weight for fillet and V-groove welds — with deposition efficiency for SMAW, GMAW, FCAW, and SAW. Imperial and metric.

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Filler metal required (actual)
Theoretical weight
Cross-section area
Weld volume
Deposition efficiency
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Weld volume formulas

Fillet weld (equal-leg): A = s² ÷ 2
V-groove butt: A = (g + t × tan(θ/2)) × t − g² ÷ (4 × tan(θ/2))
Volume: V = A × weld length
Theoretical weight: W = V × density (0.283 lb/in³ for steel)
Actual filler needed: W_actual = W_theoretical ÷ η

η: GMAW 0.90 · FCAW 0.85 · SMAW 0.60 · SAW 0.95

Filler metal examples

Example 1 — 1/4" equal-leg fillet, 10 ft (120"), GMAW

A = 0.25² ÷ 2 = 0.03125 in² · V = 0.03125 × 120 = 3.75 in³ · W_theoretical = 3.75 × 0.283 = 1.06 lbs · W_actual = 1.06 ÷ 0.90 = 1.18 lbs MIG wire

Example 2 — Same 1/4" fillet, 10 ft, SMAW (stick)

Same theoretical 1.06 lbs · W_actual = 1.06 ÷ 0.60 = 1.77 lbs of electrodes — 50% more than MIG due to stub loss and slag.

Example 3 — 60° V-groove, 1/2" plate, 1/16" root gap, 36" long, SAW

tan(30°) = 0.577 · A = (0.0625 + 0.5 × 0.577) × 0.5 − (0.0625² ÷ (4 × 0.577)) = 0.176 in² · V = 0.176 × 36 = 6.34 in³ · W_actual = (6.34 × 0.283) ÷ 0.95 = 1.89 lbs SAW wire

Weld volume questions

How do I calculate filler metal weight for a fillet weld?

First calculate the triangular cross-section: area = leg² ÷ 2. Then multiply by weld length to get volume. Multiply volume by steel density (0.283 lb/in³) and divide by the process deposition efficiency (0.90 for MIG, 0.60 for stick). A 1/4 inch fillet weld 10 feet long needs about 1.2 lbs of MIG wire.

Why does deposition efficiency matter?

Not all filler metal ends up in the weld. SMAW covered electrodes are only 55-65% efficient — the remainder becomes slag, stub loss, and spatter. Solid MIG wire is 88-95% efficient. Using the correct efficiency for your process prevents under-ordering consumables. A 10-foot 1/4 inch fillet weld requires ~1.2 lbs of MIG wire but ~2.0 lbs of stick electrodes.

What is the reinforcement factor in weld volume calculation?

Convex bead shape adds about 20% to theoretical cross-section (1.2× factor). In production, actual consumption runs 1.3–1.5× theoretical due to spatter, stub loss, and variable fit-up. This calculator uses theoretical values; add 20-30% buffer for your actual order.

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