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Sharpening angle finder

Choose a brand to get its factory angle, or set your own. Enter the height of your blade and see how high the spine sits off the stone to hold that angle.

Short answer

Spine height = blade height x sin(angle). A 48 mm tall gyuto held at 15 degrees needs its spine about 12.4 mm off the stone. The inclusive angle of a symmetric edge is twice the angle per side.

Find your angle

Factory edge: 16 degrees per side. Inclusive 32 degrees.

Example heights only. Measure your own blade from edge to spine at the heel.

Spine height off the stone

13.2 mm

Inclusive angle

32 degrees

16°13.2 mmblade 48 mmedge on the stone

Same height in stacked US coins

  • 9 pennies1.52 mm each, 13.7 mm

  • 7 nickels1.95 mm each, 13.7 mm

  • 10 dimes1.35 mm each, 13.5 mm

  • 8 quarters1.75 mm each, 14.0 mm

Spine height = blade height x sin(angle). The coin stack is a guide for holding the angle, not a jig: keep the stack at the spine near the heel.

Factory edge angles by brand

  • Shun

    Angle per side
    16 degrees
    Inclusive angle
    32 degrees

  • Miyabi

    Angle per side
    9.5 to 12 degrees
    Inclusive angle
    19 to 24 degrees

  • Global

    Angle per side
    10 to 15 degrees
    Inclusive angle
    20 to 30 degrees

  • Wusthof (current PEtec edges)

    Angle per side
    14 degrees
    Inclusive angle
    28 degrees

  • Zwilling and Henckels

    Angle per side
    15 degrees
    Inclusive angle
    30 degrees

  • Most other double bevel Japanese knives

    Angle per side
    12 to 15 degrees
    Inclusive angle
    24 to 30 degrees
Angles as published by the makers. Asymmetric edges, such as 70/30, use a different angle on each side.

How the spine height works

A blade held at 15 degrees per side on a whetstone, with blade height and spine lift labeledwhetstonespine lift hh = H x sin(angle)blade height H15° per sideedge on the stoneExample: H = 48 mm at 15° gives h = 48 x 0.259 = 12.4 mm
Hold the spine at h above the stone to keep the edge at the chosen angle per side. Measure H at the heel.

With the edge on the stone, the blade is the long side of a right triangle and the spine height is the side opposite the angle. So the height equals the blade height times the sine of the angle. At 15 degrees the spine sits a little over a quarter of the blade height off the stone; at 10 degrees, about a sixth.

Measure the height at the heel, where the blade is tallest. Toward the tip the blade gets shorter, so lower the spine a little as you move along to keep the same angle. Edge shapes are drawn in sharpening and edges.

Primary grindBevelBevelSpine

50/50 double bevel

Same bevel on both sides. Most Western and many Japanese knives.

Primary grindSmall bevelWide bevelSpine

70/30 asymmetric

Wider bevel on one side, usually the right. Common on Japanese gyuto.

Primary grindBevelBack (ura)Spine

Single bevel with ura

One bevel and a slightly hollow back. Yanagiba, deba and usuba.

Blade cross sections, spine at the top. Bevels are exaggerated so they can be seen.