Why Does A Knife Become Blunt With Use?

Have you ever noticed that your knives, once sharp, become dull and hard to use after a few months? You might be wondering why this happens and what you can do to prevent it.

A knife becomes blunt because as you cut with it, the friction of cutting wears particles off the edge of the knife. This changes the shape, taking away the honed edge responsible for its sharpness. Cutting hard material with a soft blade will quickly lead to the knife growing blunt.

Let’s look in more detail at why knives get blunter when you use them. We’re also exploring how to protect your blades from this issue to retain their sharpness for as long as possible.

Why Does A Knife Become Blunt With Use?

A knife becomes blunt because its sharp edge sticks out and is very thin. As you use the knife to cut with, you wear away at this edge, shaving off microscopic bits of metal with every slice. There is also a risk of the blade bending by whatever you are cutting. This means two forces are working to blunt the knife whenever you cut something.

Let’s start with the friction.

A blade needs to be thin to cut well because this reduces the friction and allows it to bite through the material you are cutting. The thinner the blade is, the better it will cut, so a sharp knife has a very thin edge.

However, this thin edge will get worn down quickly because there are few particles there. So when you use the knife to cut, you will constantly wear off the very thinnest tip, the cutting edge, and gradually work your way into thicker metal.

This metal will not cut as effectively because it is thicker, so it will experience more friction as it slices through things. This exacerbates the wear and tear, worsening the problem. Although only fractionally thicker, this edge is blunter and suffers from more friction.

You are constantly wearing away at the knife in small ways and gradually blunting the blade as the honed edge is worn off. This is the first thing that causes a knife to become blunt.

Let’s now move on to the second thing: the risk of bending the knife edge. Remember, the honed edge of the knife is thin, and, therefore, not very strong. If you cut something hard, this edge can bend in places. These bends will be tiny and not visible to the naked eye, but they will turn the sharp, cutting edge into a blunt, flat one.

Imagine what would happen if you tried to cut through a stone with a knife. The stone would press against the sharp, weak edge of the metal, flattening it. To a much smaller degree, the same is happening when you press the knife against food – especially tough food.

Together, these two things blunt the knife. In addition, it loses its sharp edge through wear and tear, and the edge also warps and becomes flattened when you cut into hard foods. Overall, therefore, your knife becomes blunter the more you use it.

How Can You Stop Your Knives From Becoming Blunt?

It isn’t really possible to stop your knives from becoming blunt. No matter what you do, this will happen as the knife’s edge gets worn away. However, you can make it happen more slowly by using the knife appropriately and washing and storing it correctly.

Firstly, you should choose a knife that is right for the job. For example, if you are cutting large, hard objects, you need a bigger knife. This will have a stronger cutting edge and can spread the pressure across the entire length of the blade.

Using a small knife would result in a lot of pressure on a short blade, making it much more likely to bend. Therefore, it would help if you chose your knife according to the object you are cutting.

Secondly, you should choose knives made of high-quality steel. Poor-quality metal tends to be softer and will bend and warp more easily. It will also wear down faster. On the other hand, high-quality knives will last for much longer. You can also sharpen them to extend their usefulness.

Thirdly, wash and store your knives correctly. You should wash them by hand, rather than putting them in the dishwasher, where they will get rattled and bumped by metal and ceramics. Put them on the drainer carefully to avoid damaging the blades. Then, dry and store them in an appropriate place in a drawer.

Please do not leave your knives loose in the drawer, as they will rattle and bump every time you open or shut the drawer. This means they are more likely to get damaged because they will be hitting a hard surface, which will cause friction and warping to the cutting edge.

Instead, store them in a knife block or in slots that hold them in place within the drawer. This reduces the friction and knocks, making them last for longer.

Should I Sharpen My Knives?

Yes, it would be best if you regularly sharpen your knives. By keeping your blades sharp, you reduce the friction, which slows the blunting process down. You also make cutting things easier and safer because you have to exert less pressure to make the knife cut. This reduces the risk of you injuring yourself.

Get a proper sharpening tool and learn the technique. You may find online videos like How To Sharpen Dull Knives useful. It will explain the difference between honing a knife and sharpening it and how you can do both to keep your knives in top condition.


So, why does a knife become blunt with use? Dull knives occur naturally in the kitchen, and the more you use a knife, the more quickly it will become dull. You can and should sharpen your knives, as they are much more dangerous when blunt and will make cooking considerably more work. Learn the proper technique online, so you know how to make the most of your tools.

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