MIG current follows the wire, and the wire follows the feeder dial. This calculator starts wire-feed speed from plate thickness and a rule-of-thumb factor for .023 / .030 / .035 / .045 solid steel wire: thickness in thousandths × the factor, in inches per minute. An optional amp note is about 1 A per 0.001 in of plate. Live, in the browser. Starting chart only — not a WPS.
MIG current follows the wire, and the wire follows the feeder dial.
Use it when the chart inside the machine door does not cover your material or wire, or as a sanity check on a setting. Enter the metal thickness and wire size and the page estimates wire feed speed and the approximate current it corresponds to. Start there on scrap of the same joint and tune the voltage for a steady, crackling arc.
Two shop rules stacked. First, many GMAW cards size current from plate: about one ampere per thousandth of an inch. 1/8 in plate is 0.125 in, so the note is ~125 A. Second, solid steel wire burns off at a roughly constant IPM per amp, and that constant shrinks as the wire gets fatter. Multiply the thousandths (the same number as the amp note) by the factor for the diameter on the spool.
thousandths = tin × 1000
WFSIPM = thousandths × factor
Factors on this calculator: .023 → 3.5 · .030 → 2.0 · .035 → 1.6 · .045 → 1.0
Optional amp note: ~1 A per 0.001 in of plate (same thousandths, rounded to a whole ampere).
Millimetres first become inches: tin = tmm / 25.4. Metres per minute = IPM × 0.0254.
The four factors match the solid-wire multipliers on a public Miller GMAW setup article (inches of wire per amp, with a 1/8 in / 125 A example). They are a rule-of-thumb starting chart, not a calibration of your feeder and not a welding procedure. Voltage, gas mix, position, joint, stick-out, and transfer mode are not on this calculator. Set WFS first, then walk voltage on a coupon until the arc is a crisp sizzle — not a stub into the plate, not a bird-nest at the tip.
This is not AWS A5.18, not the door chart glued to a particular machine, and not a WPS. Flux-cored wire, aluminum, stainless, and spray-transfer programs use different numbers. If the work needs a procedure, get one.
Shop check is always 1/8 in plate (125 thousandths) × the factor. Default example is the .035 row: 200 IPM.
| Wire | Factor | 1/8 in start | Typical amp band (solid steel) |
|---|---|---|---|
| .023 in (0.6 mm) | 3.5 | 437.5 IPM | ~30–130 A |
| .030 in (0.8 mm) | 2.0 | 250 IPM | ~40–145 A |
| .035 in (0.9 mm) | 1.6 | 200 IPM | ~50–180 A |
| .045 in (1.2 mm) | 1.0 | 125 IPM | ~75–250 A |
Amp bands above are the usual solid-wire windows printed next to those multipliers (Miller’s setup article lists them as a size-selection aid). They do not rewrite WFS. A 1/8 in coupon at ~125 A sits inside .030 / .035 / .045 and at the top of .023 — which is why .023 on 1/8 in is a fast feeder, not a favorite pairing. Some flux-core charts print 1.2 for .045; this page uses 1.0 for solid wire, as on that reference chart.
| Thickness × wire | Arithmetic | WFS | Amp note |
|---|---|---|---|
| 1/8 in (0.125) · .035 | 125 × 1.6 | 200 IPM | ~125 A |
| 1/8 in · .030 | 125 × 2.0 | 250 IPM | ~125 A |
| 1/8 in · .023 | 125 × 3.5 | 437.5 IPM | ~125 A |
| 1/8 in · .045 | 125 × 1.0 | 125 IPM | ~125 A |
| 16 ga (0.060) · .030 | 60 × 2.0 | 120 IPM | ~60 A |
| 1/4 in (0.250) · .035 | 250 × 1.6 | 400 IPM | ~250 A |
| 3.175 mm (1/8) · .035 | same 125 × 1.6 | 200 IPM | ~125 A |
Those seven rows use the same math as the calculator (WFS = t_in × 1000 × factor, millimetres ÷ 25.4). The usual shop check is the first row: 1/8 in on .035 → 200 IPM. Metric 3.2 mm is the labeled stand-in for 1/8 in, not 0.125 × 25.4 = 3.175 mm, so a typed 3.2 comes out one thousandth high (~201.6 IPM). Use the 1/8 preset, or type 0.125 in, for the clean 200.
Treat the calculated wire speed as the first setting, then tune by sound and bead shape. A steady, crisp crackle usually means wire speed and voltage are in balance. Popping and spatter with the wire stubbing into the plate points to too much wire for the voltage; a hissing, long arc with the wire balling up points the other way.
Stick-out changes everything. A longer electrode extension preheats the wire and lowers the current at the same wire speed, so if you weld at a long stick-out, the same dial setting runs colder. Keep stick-out consistent while you set up, and run a test bead on scrap of the same thickness and joint type before the real part.
Joint type matters as well as thickness. A fillet in a T-joint sinks heat into two plates, so it often wants more wire than a butt joint in the same material; an outside corner wants less. Position matters too — vertical-up and overhead are usually run cooler than flat.
Example: 1/8 in plate with .030 wire is 125 thousandths × 2.0 = 250 IPM, about 125 A. Run it on a scrap T-joint and adjust in small steps from there.
As a rule-of-thumb start, yes: 0.125 × 1000 = 125 thousandths; 125 × 1.6 = 200 IPM. That is also ~125 A on the optional amp note, and it is the default example on this page. It is not automatically the number for vertical-up, a wide gap, spray transfer, flux-core, or a cold machine. Open at 200, then move 10–20 IPM at a time until the puddle wets without undercut or a pile of spatter. Walk voltage after the feeder, not before.
Most small MIG welders do not have an amp meter you set. The feeder dial is inches per minute. The rule of thumb estimates the current you want from the plate (1 A per 0.001 in), then converts that current into a feeder speed with the burn-off factor. If you already know the amps you want, the same factor works: WFS = amps × factor. Type the matching thickness (amps ÷ 1000, in inches) and this calculator prints that speed.
Not on this page. Voltage sets arc length and bead shape; wire speed sets current and fill. A rule-of-thumb WFS without a voltage is still useful because you can hear voltage: stubbing means go up a little, a long harsh arc or burn-back at the tip means come down. Door charts pair a voltage with a WFS for one gas, one position, and one joint. This calculator is the WFS column of that idea, labeled as a rule of thumb, not a procedure.
This calculator uses 1.0 for solid .045, matching the reference chart the other three factors come from (1/8 in → 125 IPM). Some flux-cored and mixed-gas tables print 1.2. If your spool is flux-core, or the carton prints a different burn-off, use the carton. This calculator will not grow a second factor — the four numbers here are the solid-wire rule of thumb, full stop.
The rule of thumb is a short-circuit starting guess on mild steel with C25-style gas. Spray wants more voltage, a higher argon mix, and usually more WFS than this chart on the same plate. A 1/4 in coupon at 400 IPM on .035 may be a spray program on a 240 V machine and an overheated short-circuit on a 120 V hobby box. If the arc hisses and the puddle runs fluid, you left short-circuit. This page does not pick a transfer mode.
Not as printed. Self-shielded flux-core often runs a different WFS and a different voltage window; gas-shielded flux-core is closer to solid but still not these four factors. Stainless and aluminum have their own burn-off and a different 1 A-per-thousandth habit. Keep this calculator for solid carbon-steel wire. For stick current from rod diameter, use the stick amperage calculator — that is a different rule of thumb.
No. A WPS is a qualified document: process, filler, position, polarity, amperage or WFS range, voltage, travel, gas, preheat, and the code that owns the joint. This page is a starting guess from thickness and wire diameter so you can light a coupon without staring at a blank dial. It does not qualify a welder, a machine, or a joint. If the work needs a WPS, get one.
Use the unit you measured. US plate and wire are spoken in inches (.035 wire, 1/8 plate). Metric thickness is millimetres; the formula always converts to inches because the rule-of-thumb is thousandths and IPM. Switching units converts the thickness already typed. Wire options stay .023 / .030 / .035 / .045 with millimetre labels in the menu. Mixing a 3.2 typed as thickness in inches will invent a silo.