Approximate values
Reel Spool Capacity Calculator
Estimate yards from arbor diameter, spool width, line depth, and line diameter. The capacity printed on the reel is the measured number.
Yards are the ring volume, π × (outer radius² − arbor radius²) × width, divided by the line’s cross-section, then multiplied by 0.907. Outer radius is the arbor radius plus the depth you measure. 0.907 is the hexagonal packing density of equal circles, π ÷ (2 × √3). A loose wind holds less. The yards printed on the reel are the measurement that counts.
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Enter the arbor diameter. The estimate stays blank until that measurement is in.
π × (outer radius² − arbor radius²) × width × 0.907 ÷ line cross-section.
Sources: JAFTMA reel capacity measurement · Hexagonal circle packing
Lithvox line and leaders