Wedge Ratio Calculator

A knife is sold on two numbers the maker supplies — a steel name and a hardness figure — and neither describes the cut. What decides whether a blade opens a butternut squash or cracks it is the cross-section sitting behind the apex. Put calipers on the spine and a rule on the height, enter both here, and you have the one figure nobody prints.

Measurement units

Spine thickness at the heel (mm)

Calipers on the spine, directly above the heel — not on the bolster.

Blade height at the heel (mm)

Apex to spine at the same station, measured square to the edge.

Distal taper (optional second station)

One station tells you how the heel cuts. Add a second reading 30 mm back from the tip and you also get how fast the spine thins toward the point.

Spine thickness 30 mm from the tip (mm)

Same calipers, same spine, 30 mm back from the point.

Blade length, heel to tip (mm)

Cutting edge only, from the heel to the point.