Spearfishing Calculators, Tools & Data

SpearMetric is a set of free, no-nonsense tools for spearfishing equipment: measurement calculators, reference charts and comparison guides.

Start with speargun sizing, band length and shaft compatibility. Every tool shows its assumptions and points back to manufacturer specifications.

Calculators

Rule-based reference size ranges by hunting environment, with visibility and experience context.

Estimate band length from a measured pull distance, wishbone length and your stretch ratio.

Calculate measured stretch factor from relaxed and stretched band lengths.

Geometry-based shaft, overhang and assembled spear length calculations.