Stainless steel coil buyers often need to convert between weight, length and coil dimensions. The key constant is density: about 7.93 g/cm³ for 304/316L austenitic grades and about 7.70 g/cm³ for 430 ferritic.

Weight of strip (kg) = width (m) × thickness (mm) × length (m) × density (g/cm³)

For a full coil, length is often not known, so use the coil's outer diameter (OD), inner diameter (ID) and width:

Length (m) ≈ π × (OD² − ID²) / (4 × thickness)

Worked example: 304 coil, OD 1500 mm, ID 508 mm, thickness 0.5 mm, width 1219 mm.

• Cross-section area of the wound strip ≈ π × (1.5² − 0.508²) / 4 = 1.566 m² • Length ≈ 1.566 / 0.0005 = 3132 m • Weight ≈ 1.219 × 0.5 × 3132 × 7.93 = 15,140 kg

Practical notes:

• Actual weight includes edge trim and mill tolerances — expect ±1%–3% versus calculation. • Coil weight is limited by crane capacity and handling; common export coils are 5–15 t. • Ask the mill for the coil schedule (ID, OD, weight range) before booking freight; overweight coils may not fit the container payload.

These formulas are estimates for planning, not for invoicing; final weight comes from the mill scale ticket.