Knife Sharpening Angle: 15 vs 20 Degrees Explained

Most kitchen knives are sharpened between 15 and 20 degrees per side. Japanese-style double-bevel blades sit near 15°, traditional German blades near 20°, and single-bevel Japanese knives are ground on one face only. Thinner angles cut better; thicker angles last longer under abuse.

What a sharpening angle actually is

The sharpening angle is the angle between the face of the stone and the face of the blade as you sharpen. Almost every number you will read — 15°, 17°, 20° — is quoted per side.

That matters, because a knife ground at 20° on the left and 20° on the right has a total inclusive edge angle of 40°. Some sharpener manufacturers quote the inclusive figure instead, which is why you will occasionally see "40 degrees" advertised for what is really an ordinary 20° edge. When a number looks twice as big as it should, it is almost always the inclusive angle.

The angle is what decides the shape of the very tip of the steel. A narrow angle puts less metal behind the cutting edge: the blade parts food with less force and feels keener. A wide angle leaves more metal behind the edge: the knife is blunter to start with but much harder to chip or roll.

Knife sharpening angle by knife type

• 10–12° per side — very thin, very keen. Sushi and sashimi work, precision slicing, and thin-ground hand-forged kitchen blades. Not for bone or frozen food.
• 15° per side — the standard for Japanese-style double-bevel kitchen knives: gyuto, santoku, nakiri, bunka, petty. The best all-round balance for home cooking.
• 17–20° per side — traditional German and Western chef knives, and most factory-set kitchen knives. More durable, slightly less keen.
• 20–25° per side — heavy work. Cleavers that meet bone, butchery, and outdoor and hunting blades.
• Single bevel (one side only) — yanagiba, usuba and traditional single-bevel kiritsuke. Ground on the face side at roughly 10–15° with a flat or slightly hollowed back.

Treat these as bands, not laws. The right angle for a given knife is the thinnest one its steel and its job will tolerate.

Japanese, German, or somewhere in between

The old rule was simple: Japanese knives 15°, German knives 20°. It is less true every year, because Western makers have been thinning their edges and many now leave the factory at 15°.

The reason for the original split is hardness. Japanese kitchen steels are typically run harder — often 59 to 62 HRC — and harder steel can support a thinner edge without the fine tip rolling over. Softer Western steels around 55 to 57 HRC need more metal behind the edge or they deform. If you want the longer version, our guide to the best hardness rating for kitchen knives covers the trade-off in full, and edge retention in kitchen knives explains what actually keeps an edge alive.

The practical takeaway: match the angle to the steel, not to the country of origin printed on the box.

How do I know if my knife is 15 or 20 degrees?

You do not have to guess. Colour the existing bevel with a permanent marker, take two or three light passes on a stone at the angle you think is right, and look at what came off.

• Ink gone from the whole bevel — you matched the existing angle.
• Ink gone only near the very edge — you are sharpening too steeply, at a wider angle than the knife was ground.
• Ink gone only up near the shoulder of the bevel, edge untouched — you are too shallow.

Adjust and repeat until the ink lifts evenly. This works on any knife, tells you the truth about the blade in your hand rather than what the manufacturer claims, and costs nothing.

If the maker publishes the figure, use it as the starting point. Our Torii blades are set at 12° per side, so a Torii goes back on the stone at 12°, not at the 20° a generic sharpener would default to.

Finding and holding the angle without a jig

Angle guides and clamp systems work, but you can hold a repeatable angle by hand with two tricks.

The paper fold. Fold a square of paper corner to corner and you have 45°. Fold it again and you have 22.5°. Fold once more and you have about 11°. Stand the folded wedge next to your stone and use it as a visual reference until your hands learn the position.

The spine height rule. For a typical chef knife, lifting the spine roughly the width of two stacked coins off the stone puts you in the 15° region. Wider blades need more lift for the same angle, narrower blades less — which is why the marker test above beats any rule of thumb.

Then the part nobody wants to hear: consistency beats precision. An edge held steadily at 18° will outcut an edge that wandered between 12° and 22° chasing 15°. Lock your wrist, move from the shoulder, and keep the same position for every pass on that side. Our whetstone guide walks through the stroke itself, and sharpening a Japanese chef knife covers angles and grits for thinner Japanese geometry.

What happens if you sharpen at the wrong angle

Nothing dramatic, and nothing permanent — but you waste time and steel.

Too shallow, and the stone grinds the shoulder of the bevel while never reaching the actual cutting edge. You will sharpen for twenty minutes and the knife will still not cut paper, because you never touched the part that does the cutting.

Too steep, and you cut a new, blunter micro-bevel right at the tip. The knife will feel sharp for a day and then go dull quickly, because that thickened edge has to push through food rather than part it.

Far too thin for the steel, and the edge will roll or chip the first time it meets a bone, a frozen edge or a stoneware plate. This is the one genuine risk, and it is why a cleaver meant for bone should never be taken down to a slicing angle.

In every case the fix is the same: re-establish one consistent angle along the whole blade and work until a burr forms evenly from heel to tip.

Do you need to sharpen both sides?

On a double-bevel knife — which is nearly every Western and most Japanese kitchen knives — yes. Sharpen one side until you can feel a fine burr along the full length of the edge, then do the same number of passes on the other side, then alternate lighter strokes to remove the burr.

Symmetry is not sacred. A 50/50 grind is standard, but some Japanese double-bevel knives are ground closer to 70/30, favouring the right-hand side. Match whatever the blade already has, which the marker test will show you.

On a true single-bevel knife, sharpen the front bevel only and never grind the back flat — just remove the burr there with the lightest possible pass.

What do professional sharpeners use?

Professionals use water stones and a controlled angle, in that order of importance. A coarse stone around 400–1000 grit to set the bevel, a medium stone around 2000–3000 to refine it, and a finishing stone from 5000 upward for a polished edge.

Many use a fixed-angle jig for repeatability on customer knives; most also sharpen freehand for their own. Almost none use the pull-through devices sold in supermarkets, which drag carbide teeth through the edge at a fixed, usually steep, angle and remove far more steel than any stone would. If your knife is worth sharpening, it is worth a stone.

Between sharpenings, a honing rod realigns the edge without removing steel — a different job at a slightly steeper angle than sharpening. Our guide to sharpening versus honing explains when each one is the right call.

The angles on our knives

We publish these so you never have to guess on a stone.

The Torii line is hand-forged 7Cr17MoV high carbon steel with a 12° edge per side — a thin, deliberately keen geometry that rewards being sharpened back at 12° rather than at a generic 20°. The Damascus Dynasty blades layer 67 folds around a cobalt-enriched 10Cr15CoMoV core hardened to 60±2 HRC, and that hardness is exactly what lets a thin edge survive real prep. Feather Forge wraps 73 layers of feather Damascus around an AUS-10 core on a full tang, and Bara Forge runs a 10Cr17MoV core at 60 HRC under layered forged steel.

Every one of them is hand sharpened and oiled before it ships, so the first edge is already set correctly — your job is only to put it back the same way.

Sharpening angle questions

What angle should I sharpen a chef knife at?

15° per side for a Japanese-style chef knife or gyuto, and 17–20° for a traditional German chef knife. If the maker publishes a figure, use it. Our Torii chef knives are set at 12° per side.

Is a 15 or 20 degree angle better?

Neither is better in the abstract. 15° cuts more cleanly and suits harder steels and careful home cooking. 20° is more durable and suits softer steel or a knife that meets bone, shells and hard boards. Choose by what the knife does.

Can I change the angle on a knife I already own?

Yes, but it takes work. Going thinner means grinding away the whole existing bevel with a coarse stone before you see any benefit — expect a long session. Going thicker is quick but permanent until you regrind. Make sure the steel is hard enough before you thin an edge.

Does a thinner angle mean the knife dulls faster?

Under hard use, yes, because there is less steel supporting the edge. Under normal kitchen use on a wooden board, a thin edge on a hard steel will often outlast a thick edge on a soft one. Hardness and cutting technique matter as much as the number.

Shop the range

A good angle is only worth having on steel that can hold it. Browse our chef knives, the Japanese chef knives built around thinner geometry, or the full Damascus range. Every blade is hand sharpened and oiled before it ships, backed by a 99-day home trial and a free lifetime guarantee — the sharpest blades you will ever use or your money back.

More reading: Types of Steel for Knives: The Complete 2026 Guide covers which steels can hold a thin edge and which cannot.