Knife Sharpening Angles, With a Free Angle Tool
Sharpening angle tool
Lift the spine 12.2 mm off the stone
About 7 stacked US quarters.
Show the working
The short answer. Sharpen most Japanese double-bevel knives at 12–15° per side and most German knives at 17–20° per side. To hold an angle on a whetstone, lift the spine by the blade height times the sine of the angle: about 12 mm for a 47 mm-tall gyuto at 15°.
On this page 5 sections
Sharpening angle chart
| Knife | Angle per side | Why |
|---|---|---|
| Japanese slicers (sujihiki, gyuto for fine work) | 10–12° | Hard steel, cutting soft food; thinnest edge that won't chip |
| Japanese double-bevel (gyuto, santoku, nakiri, petty, bunka) | 12–15° | Hard steel (around HRC 60+) supports a thin edge |
| German / Western kitchen knives | 17–20° | Softer steel (around HRC 56–58) needs a sturdier edge |
| Cleavers, outdoor and pocket knives | 20–25° | Impact and twisting; durability over keenness |
| Single-bevel (yanagiba, deba, usuba) | Follow the factory bevel | Lay the wide bevel flat on the stone; see the Japanese knife guide |
"Per side" matters: a 15° per side edge has an inclusive (total) angle of 30°. Manufacturers sometimes quote the inclusive angle, so check which one you're reading.
How the angle tool works
When the edge sits on the stone and you tilt the blade, the spine rises. The higher the blade, the more it rises for the same angle. The tool works out that rise with one line of trigonometry:
lift = blade height × sin(angle)
Then it divides by 1.75 mm, the thickness of a US quarter, so you can stack coins under the spine as a guide while you learn the feel. Open "Show the working" under the result to see the sum for your numbers.
Worked example
A 210 mm gyuto is about 47 mm tall at the heel. At 15° per side: 47 × sin(15°) = 47 × 0.259 = 12.2 mm. That's about seven quarters. At 20° the same knife needs 47 × 0.342 = 16.1 mm, about nine quarters. Notice how a few millimetres of lift changes the angle a lot, which is why a steady hand matters more than the exact number.
Blade height shrinks toward the tip, so keep the same angle, not the same lift, as you move along the edge. Lower the spine slightly as you reach the tip.
How to hold a steady angle
- Marker trick. Colour the edge bevel with a permanent marker, take a few strokes, and look. If the ink is gone only at the very edge, your angle is too high; only at the shoulder, too low.
- Coins or a clip-on guide for the first few sessions, then go by feel.
- Lock your wrist and move from the shoulder and elbow, so the angle doesn't rock with each stroke.
- Light pressure. Heavy pressure makes the blade tilt and rounds the edge.
Angle questions
What angle are Japanese knives sharpened at?
Most double-bevel Japanese kitchen knives come at about 12–15° per side. Some makers put a slightly asymmetric edge on them (for example steeper on one side); you can keep it or sharpen both sides evenly.
Can I sharpen a German knife at 15°?
You can, and it will feel sharper, but the softer steel rolls and dulls faster at that angle. 17–20° is the better balance for German knives.
Does the angle have to be exact?
No. Being consistent matters more than hitting a number. An edge sharpened steadily at 16° beats one that wanders between 12° and 18°.