Holding a consistent angle is the secret to a sharp knife. This calculator tells you exactly how high to lift the spine off your whetstone for any edge angle — or, if you already know the height, what angle you are really sharpening at.
How to use the sharpening angle calculator
- Measure your blade width from the edge to the spine at the heel.
- Pick a knife type or type the angle per side you want.
- Lift the spine to the height shown — a stack of coins or a small wedge makes a handy guide.
- Use the reverse mode to check the angle you have been using.
Which sharpening angle should I use?
- 12–15° — Japanese kitchen knives, sushi and fillet knives: very sharp but delicate.
- 17–20° — Western chef knives and everyday pocket knives: the best balance of sharpness and durability.
- 22–25° — hunting, survival and outdoor knives that see hard use.
- 30°+ — machetes, hatchets and axes.
Frequently asked questions
Is the angle per side or inclusive?
The calculator uses the angle per side, which is how most sharpeners and manufacturers describe it. The inclusive (total) angle is double that number.
Why does blade width matter?
For the same angle, a wider blade needs the spine lifted higher. Spine height = blade width × sin(angle).
Can I sharpen a German knife at 15°?
You can, but softer Western steel may roll or dull faster at a thin angle. 17–20° is usually the better choice.