Weld Metal & Filler Consumption Calculator
Work out how much weld metal a joint takes and how much electrode or wire to buy. Choose a fillet, single-V, double-V, bevel, square or U groove, enter its size and length, and get the cross-section, the weight of weld metal and the filler needed after deposition losses.
How to Use
- Pick the joint: fillet, single V, double V, single bevel, square groove or U groove.
- Enter its dimensions with their units: the leg for a fillet; plate thickness, root opening, root face and angle for a groove (the root radius too for a U).
- Add the reinforcement height (the cap above the plate, or the convexity of a fillet) if you want it counted, then the weld length and how many identical welds there are.
- Choose the metal and the process. The process sets the deposition efficiency: 60% for stick, 80% flux-core, 90% or 98% MIG, 100% submerged arc.
- Enter a package size (a 10 lb can, a 33 lb spool) to see how many to buy. Show Work lists the area, the weight and each conversion.
Worked Example
A 1/4 in fillet, 10 ft, with stick electrodes. Section = 0.25² ÷ 2 = 0.03125 in², plus 1/32 in of convexity over the 0.3536 in face: 2/3 × 0.3536 × 0.03125 = 0.007366 in², so 0.03862 in² in all. At 0.283 lb/in³ that is 0.03862 × 12 × 0.283 = 0.1311 lb per foot and 1.311 lb for 10 ft. At 60% efficiency you need 1.311 ÷ 0.60 = 2.186 lb of electrode.
A 3/8 in single V butt weld, 20 ft, MIG. With a 60° included angle, 1/8 in gap and 1/16 in root face: 0.125 × 0.375 + 0.3125² × tan 30° = 0.1033 in²; a 1/16 in cap over the 0.4858 in opening adds 0.02024 in², 0.1235 in² in all. That is 0.4194 lb per foot, 8.388 lb over 20 ft, and 8.388 ÷ 0.98 = 8.559 lb of wire, about a quarter of a 33 lb spool.
The common mistake: buying the weld metal weight. The 10 ft fillet holds 1.311 lb of steel, but stick electrodes lose slag, spatter and the stub, so 1.311 lb of electrode runs out 60% of the way along; you need 2.186 lb. Taking the fillet section as leg² instead of leg² ÷ 2 is the other slip: it doubles the answer, 0.212 lb per foot instead of 0.1061 before convexity.
Show Work
Formulas
Where the Filler Goes
Not every pound of filler bought ends up in the joint. In Fabricators’ and Erectors’ Guide to Welded Steel Construction, published by the James F. Lincoln Arc Welding Foundation, Omer Blodgett and Scott Funderburk list the efficiency factors used for costing: 60% for shielded metal arc (stick) welding, where slag, spatter and the discarded stub end all count as losses; 80% for flux-cored; 90% for gas metal arc under CO₂ and 98% under mixed gas; and 100% for submerged arc, with the flux not included. Lincoln Electric’s GMAW guide splits MIG further by transfer mode: short-circuit under argon blends at 93% or more, under 100% CO₂ 90 to 93%, and spray and pulsed spray about 98%.
The same guide makes the point that filler is a small part of welding cost: in its example, the electrode is about 6% of the cost of a stick-welded joint, and labour and overhead are the rest. Weld size still matters, because a bigger section is both more filler and more arc time. A 5/16 in fillet has 1.56 times the section of a 1/4 in fillet, since area goes with the square of the leg.
Welding fume is part of the job: OSHA’s fact sheet on controlling hazardous fume ranks flux-cored, stick, MIG and TIG in decreasing order of fume, and asks for local exhaust ventilation close to the arc, especially with stainless steel, which can give off hexavalent chromium.
About This Tool
This calculator finds the cross-section of the weld metal for six joint shapes, adds a reinforcement or convexity cap as a parabolic segment, and turns it into weight with Lincoln Electric’s densities for carbon and stainless steel or PubChem’s for aluminium. It divides by the deposition efficiency for the process to give the filler to buy, and the number of cans or spools. The U groove is an approximation; for TIG rods or any other process, enter your own efficiency.
Real joints vary with fit-up, so treat the result as an estimate and allow for tacks, starts and stops and practice pieces. Everything runs in your browser; nothing you enter is sent anywhere.
Related tools: Fillet Weld Size & Strength Calculator, MIG Wire Feed Speed & Deposition Rate Calculator, and Welding Cost Estimator.
Frequently Asked Questions
How much weld metal is in a fillet weld?
A fillet with equal legs has a triangular section of leg² ÷ 2. A 1/4 in fillet is 0.25² ÷ 2 = 0.03125 in², and at 0.283 lb/in³ for steel that is 0.03125 × 12 × 0.283 = 0.1061 lb of weld metal per foot. Convexity adds more: 1/32 in of it brings the section to 0.03862 in² and 0.1311 lb per foot.
How much stick electrode do I need per foot of weld?
Divide the weld metal by the deposition efficiency. Blodgett and Funderburk’s guide for the James F. Lincoln Arc Welding Foundation uses 60% for stick, covering slag, spatter and stub ends. A 1/4 in fillet with 1/32 in convexity needs 0.1311 ÷ 0.60 = 0.219 lb of electrode per foot, close to the 0.211 lb per foot Lincoln’s stick electrode guide lists for 1/4 in fillets.
What deposition efficiency should I use?
The same guide gives stick (SMAW) 60%, flux-cored (FCAW) 80%, MIG (GMAW) 90% with CO₂ and 98% with mixed gas, and submerged arc 100% (flux not included). So 10 lb of weld metal takes 16.67 lb of stick electrode but only 10.2 lb of MIG wire under mixed gas. For TIG or anything else, enter your own figure.
Why does a double V use less weld metal than a single V?
Each half is only half as deep, and area grows with the square of depth. On 20 mm plate with a 60° included angle, 2 mm gap and 2 mm root face, a single V holds 227.1 mm² of weld metal and a double V 133.5 mm², about 41% less, before the caps.
What density should I use for weld metal?
Lincoln Electric uses 0.283 lb/in³ (7.83 g/cm³) for carbon steel and lists 0.29 lb/in³ (8.0 g/cm³) for austenitic stainless; aluminium is 2.70 g/cm³ (PubChem). The 7.85 g/cm³ often quoted for steel differs by about 0.2%. For other alloys choose Custom and enter the density.
How do I use the Weld Metal & Filler Consumption Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Ordering electrodes
10 ft of 1/4 in fillet with 1/32 in convexity is 1.311 lb of weld metal, so 2.186 lb of stick electrode at 60%: one 10 lb can covers it.
Butt welds in plate
A 3/8 in single V at 60°, 1/8 in gap and 1/16 in root face with a 1/16 in cap is 0.1235 in²; 20 ft of it takes 8.388 lb of steel and 8.559 lb of MIG wire.
Thick-plate jobs
5 m of 20 mm double V with 1.5 mm caps is 158.3 mm² and 6.201 kg of weld metal, so 7.751 kg of flux-cored wire at 80%: one 15 kg spool.
Quoting
A 1 in U groove with a 1/4 in root radius, 10° walls and a 1/8 in root face holds about 1.73 lb per foot with a 1/16 in cap, so 4 ft is 6.922 lb of submerged-arc wire.
Metric fillets
A 6 mm fillet is 18 mm², 0.141 kg of steel per metre, or 0.235 kg of stick electrode per metre at 60%.
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