Explainer

Edge angle gets quoted in degrees — 20, 25, 17 — usually without saying whether that is per side or inclusive, which is the first thing worth pinning down.

Per side versus inclusive

A knife sharpened at “20 degrees” almost always means 20 degrees per side, giving a 40-degree inclusive edge.

Some manufacturers quote the inclusive figure instead. When a specification looks unusually low or high, that is usually the reason. Comparing a per-side number against an inclusive one is comparing nothing.

The trade

A more acute angle produces a thinner apex. Thinner apexes cut with less force, because less material has to be pushed aside.

The same thin apex has less steel behind it, so it deforms and chips more readily. A blunter angle puts more metal behind the edge and survives more abuse while requiring more force to cut.

This is the same trade discussed in our piece on blade steel, expressed as geometry rather than metallurgy — and the two interact. A hard steel can hold a more acute angle than a soft one before deforming.

Rough ranges and what they suit

Very acute edges suit clean slicing of soft material — kitchen work, filleting, hide.

Mid-range edges are the general-purpose compromise, and where most factory outdoor knives arrive.

Obtuse edges suit chopping, wood and impact, where survival matters more than effortless slicing. Axes and machetes sit well up this range for exactly that reason.

These are ranges rather than rules, because the right angle depends on the steel, the heat treatment and the job.

The microbevel

A common approach is to grind the main bevel at a lower angle and then add a tiny secondary bevel at a slightly higher one right at the apex.

That gives most of the cutting benefit of a thin grind with a more durable apex, and it makes touch-ups fast because you are only working a sliver of steel.

The practical version

Most people are better served by consistency than by chasing a number. An edge held at a steady angle, whatever it is, outperforms one that wanders between 15 and 30 degrees over the length of the blade.

If your knife chips, go blunter. If it will not cut without force, go more acute. That feedback loop will get you to the right angle for your use faster than any chart.

This article was researched and drafted with the assistance of AI tools and reviewed, fact-checked and edited by Leonidas Clark before publication.