How to Use the Steel Coil Length & Weight Converter
A steel coil is just a flat sheet rolled up — unroll it and it's a long strip of uniform thickness. Once you know the volume and density, length and weight convert freely into each other. Use this when a coil's tag lists weight but you need to know its unrolled length, or when you know the length you need and want an estimated weight before ordering.
The calculation is weight (lb) = length (ft) × width (in) × thickness (in) × 3.4028, using the standard steel density factor derived from 490 lb/ft³. Solving for length instead gives length = weight ÷ (width × thickness × 3.4028). Pick a conversion direction, enter thickness and width, and fill in whichever value you know — length or weight.
This calculation assumes the coil fully unrolled into a flat strip, so it isn't meant for estimating length from a wound coil's outer and inner diameter — that needs an extra wind-density factor and introduces more error. Using accurate measured thickness and width matters most for thin-gauge material, where mill tolerance has the largest relative effect, so cross-check the nominal thickness on your order against a measured sample when it matters.
Frequently Asked Questions
Multiply volume (length × width × thickness) by the steel density factor 3.4028 lb per ft-in² to get weight, or divide weight by (width × thickness × 3.4028) to get length. A coil is just a rolled-up flat sheet, so this formula applies directly.
This calculator only converts based on thickness, width, and length or weight. Estimating length from outer/inner diameter needs an additional wind-density factor that introduces more error, so measured thickness, width, and weight give more reliable results.