MIG Weld Deposition Rate Calculator

From wire-feed speed to deposited pounds per hour

Wire-feed speed is a length rate, not a weight rate. A larger-diameter wire contains more steel in every inch, so diameter must be squared before multiplying by inches fed per minute. Lincoln Electric combines the solid-wire cross-section and steel density into a published planning constant of 13.1:

Theoretical feed weight (lb/hr) = 13.1 × diameter² × WFS
Deposited metal (lb/hr) = theoretical feed weight × electrode efficiency

The first number is sometimes called melt-off rate: how much solid wire is fed toward the arc in an hour, before transfer loss. The second is deposition rate: how much becomes weld deposit after the explicit efficiency factor. The model covers solid carbon- and low-alloy-steel GMAW wire. It does not model tubular metal-cored or flux-cored wire, aluminum, submerged arc, TIG filler addition, or stick electrodes.

Worked example: 0.035-inch wire at 300 ipm

The default example uses 0.035-inch solid steel wire, 300 ipm, 93% efficiency, a known 10-pound deposit, and an 11-pound spool priced at $45:

• 13.1 × 0.035² × 300 = 4.8143 lb/hr theoretical wire feed.
• 4.8143 × 0.93 = 4.4773 deposited lb/hr.
• 10 lb ÷ 4.4773 lb/hr = 2.2335 arc hours, or about 134 minutes.
• 10 lb ÷ 0.93 = 10.753 lb of wire required before package rounding.
• 10.753 lb fits within one 11-pound spool, so package cost is $45.
• The calculated package balance is about 0.247 lb; it is inventory, not assumed waste.

Choose efficiency from evidence, not optimism

Lincoln Electric defines electrode efficiency as the percentage of electrode that actually ends up in the weld deposit. Its GMAW guide gives contextual examples: short-circuit transfer with an argon/CO₂ blend at 93% or higher, short-circuit with 100% CO₂ at 90–93%, globular transfer at roughly 85–90% depending on gas, and axial spray or STT at 98%. The guide describes pulsed-spray planning at generally 98% while warning that application conditions can reduce it.

Those are reference points, not instructions to change the process. The calculator keeps efficiency as a free input because actual spatter, clipping, setup, transfer mode, consumable, and housekeeping differ. TWI recommends a direct validation when accuracy matters: weigh a plate, deposit for a fixed recorded arc time, then reweigh it. Use the measured gain divided by arc hours as the shop-specific deposited lb/hr.

Deposit weight, wire required, and purchased wire are different

Required deposit weight belongs to the finished joint. Wire required divides that deposit by efficiency. Purchased wire rounds the requirement up to whole user-selected packages. These distinctions prevent three common estimating errors: treating all fed wire as deposited metal, treating reusable spool balance as process loss, or pricing a fractional package when the job requires another full spool.

TWI separately notes small GMAW losses from clipping wire at the contact tip, unusable reel ends, and damaged wire or reels. If your measured efficiency does not capture those inventory losses, keep a separate tracked shop allowance rather than silently lowering a qualified production rate. Package compatibility, wire classification, storage, shielding gas, and the applicable procedure still require independent verification.

Arc time is not elapsed job time

This page calculates arc-burning time only: deposit weight divided by deposited pounds per arc hour. It does not include preparation, fit-up, tacking, positioning, interpass cleaning, inspection, spool changes, breaks, or repair. Send the arc hours to the welding time and labor cost calculator and use your own observed operator factor when estimating elapsed work.

When this calculator is the wrong tool

• You need procedure settings: this page never chooses voltage, amperage, WFS, travel speed, gas, transfer mode, or wire.
• You do not know deposit weight: start with the joint-geometry filler calculator or a qualified takeoff.
• You use cored or non-steel wire: use product-specific manufacturer data; the solid-steel constant does not apply.
• You need clock or labor time: measure non-arc work and use a separate operator-factor model.
• You need acceptance: a WPS, code, drawing, engineer, inspector, and manufacturer instructions govern the weld.

Sources and methodology

• Lincoln Electric: Gas Metal Arc Welding Guide — solid-steel deposition-rate equation, 0.283 lb/in³ steel density, and electrode-efficiency definition and examples.
• TWI: Welding Costs — distinction between deposited metal and purchased consumable, including ordinary GMAW inventory losses.
• TWI: Welding Costs, continued — timed before-and-after weighing method for an accurate parameter-specific deposition rate.

Sources and behavior were reviewed on 2026-07-31. The model and package math are unit-tested against hand calculations and invalid boundaries. No standards table, procedure setting, certification claim, or acceptance decision is reproduced or inferred.