Have you ever wondered, or have you ever been asked how many inches of wire are in one pound of filler metal? You may have been asked something like: “How many inches of wire are there in a 25LB spool of .035” ER70S-6 mig wire?” Typically, this questions is asked when someone is trying to estimate costs or find out how long this spool will last at a given wire feed speed.
You can download your free Cheat Sheet for Inches of Wire per Package (of wire) here. You can also keep reading below to see how we can calculate this for any diameter, and not just the common ones such as .023”, .025”, .035”, etc.
Please note, these calculations are for solid wires only and do not apply to flux-cored or metal-cored wires. The calculation is simple, but we need to know the following:
- Filler metal type (carbon steel, stainless steel or aluminum)
- Specific density of the material
- Diameter of the wire
- Weight of package (weight of filler only)
What we are calculating is the volume of material and then multiplying it by the density of that material to arrive to our answers. The density of steel and stainless steel are pretty close (0.283lb/cu-in and 0.289lb/cu-in respectively). The density of aluminum is 0.098lb/cu-in so please be careful to use the right density.
Our formula is the following:
π = 3.14159where,
D = wire diameter
d = density of filler metal
Once we have inches per pound all we need to do is multiply this number by the number of pounds per package. So, per the example above the number of inches of .035” ER70S-6 per 25-pound spool is: