Estimate the length, volume and weight of filament, wire or rope wound on a spool. Pick a material, set the spool size, and the results update as you type.
Formula: Length = (Spool Width / Material Diameter) × π × Σ (Inner Diameter + n × 2 × Material Diameter). The maximum theoretical fill for round material is about 90.7% (hexagonal packing); real-world winding is typically 75–85%. Length assumes perfect winding and the fill figure assumes round packing; estimates are approximate and vary with winding tightness.