# Welding Calculator

Get recommended welding parameters for MIG, TIG, and stick welding. Enter material thickness and type to get amperage, wire/rod size, gas flow rate.

## What this calculates

Getting the right welding parameters is the difference between a strong, clean weld and a messy, weak joint. This calculator provides recommended amperage, filler wire or rod diameter, shielding gas flow rate, and travel speed based on your material thickness, joint type, welding process, and base metal.

## Inputs

- **Material Thickness** (in) — min 0.02, max 2 — Thickness of the base material
- **Joint Type** — options: Butt Joint, Fillet / T-Joint, Lap Joint, Tee Joint — Joint configuration affects heat input and technique
- **Weld Process** — options: MIG (GMAW), TIG (GTAW), Stick (SMAW) — Welding process determines wire/rod and gas settings
- **Material** — options: Mild Steel, Stainless Steel, Aluminum — Material affects amperage, gas, and filler selection

## Outputs

- **Recommended Amperage** (A) — formatted as text — Amperage range for the given thickness and process
- **Wire / Rod Diameter** — formatted as text — Recommended filler wire or electrode diameter
- **Gas Flow Rate** (CFH) — formatted as text — Shielding gas flow (MIG/TIG only)
- **Travel Speed** (in/min) — formatted as text — Approximate travel speed for consistent bead
- **Passes Needed** — formatted as text — Number of weld passes for complete penetration

## Details

The fundamental rule for MIG welding mild steel is 1 amp per 0.001 inches of thickness. A 1/4-inch plate needs approximately 250 amps. TIG welding uses slightly less current, and aluminum requires higher amperage due to its higher thermal conductivity. These are starting points; fine-tune based on your specific machine, wire feed speed, and joint fit-up.

Filler wire diameter should match material thickness. For MIG: use .023-.030" wire for sheet metal (up to 1/8"), .030-.035" for medium plate (1/8" to 3/8"), and .035-.045" for heavy plate (3/8"+). For TIG, common filler rod sizes are 1/16", 3/32", and 1/8". Using too large a filler for thin material wastes heat and distorts the workpiece.

Shielding gas protects the weld from atmospheric contamination. MIG welding steel uses 75/25 argon/CO2 (best all-around) or 100% CO2 (deeper penetration, more spatter). TIG uses 100% argon for all metals. Aluminum MIG uses 100% argon. Gas flow of 25-30 CFH is standard; increase in drafty conditions, decrease in enclosed spaces.

## Frequently Asked Questions

**Q: How do I determine welding amperage?**

A: The general rule for steel is 1 amp per 0.001 inches of material thickness. For 1/4-inch steel, start at about 250 amps. Adjust down 10-15% for stainless, and up 10-40% for aluminum. These are starting points; fine-tune based on weld appearance, penetration, and your specific equipment.

**Q: What gas should I use for MIG welding?**

A: For mild steel, use 75% Argon / 25% CO2 (C25) for the best combination of penetration, spatter control, and bead appearance. For stainless, use a tri-mix (90% He, 7.5% Ar, 2.5% CO2) or 98% Ar / 2% CO2. For aluminum, use 100% Argon. Flow rate is typically 25-30 CFH.

**Q: When do I need multiple weld passes?**

A: Generally, material over 1/4-inch thick requires multiple passes. Each pass deposits approximately 1/8 to 1/4 inch of weld metal. A 1/2-inch plate typically needs 2-3 passes, and 1-inch plate may need 6-8 passes. The root pass penetrates the joint, fill passes build up the weld, and the cap pass provides the finished surface.

**Q: Can I stick weld aluminum?**

A: While aluminum stick electrodes exist (E4043), they produce poor results compared to MIG or TIG. Aluminum stick welding is extremely difficult, produces excessive spatter, and creates weak, porous welds. MIG with a spool gun or TIG (AC) are the proper processes for aluminum.

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Source: https://vastcalc.com/calculators/construction/welding
Category: Construction
Last updated: 2026-04-21