How Do I Know if my Knife is Sharp or Dull? (2024)

Everyone knows a sharp knife is the best knife, but how doyou know if your knife is sharp? Dulling is a process that happens over time,and often your cutting/slicing technique adjusts to the dullness until youdon’t even remember what “sharp” is. We want you to know how to spot dull!

Today in the Workshop, Josh and Kyle from Work Sharp walkyou through easy ways you can test your knives to assess how sharp (or not)they are.

Easy Sharpness Tests

While there are highly scientific and expensive ways to assesssharpness, here are three ways to determine the sharpness of your knife quicklyand easily.

1. Visual Inspection of the Edge: You can see“dull”. The first test for sharpness is to look at the edge of your knife. Holdit perfectly straight and then slowly tilt the knife to the left and right,looking for areas where the light catches on the edge. Any part of the edgethat reflects light is dull, and the edge has been removed or pulled to theside. Chips and nicks can also be visually observed. If you cannot capturelight across the entire edge, you are sharp!
2. Fingernail Sharpness Test: Testing sharpnesson your fingernail is the go-to sharp test for Work Sharp at knife shows andsharpening events. The technique is simple… gently tap the edge of the bladeagainst your fingernail. Your knife is sharp if the blade bites in, and dull ifit deflects or slides. Start from the heel (closest to the handle) and tap tothe tip, looking for any areas that are not sharp. If you feel uncomfortableusing your fingernail to test sharpness, a Sharpie will also work. Hold theSharpie at a 45-degree angle and gently tap the knife’s edge against the bodyof the pen; it will stick if it is sharp.
3. The Tomato Test: Popularized in themainstream by decades of cooking shows, the Tomato Test is the most commonkitchen tess to prove sharpness. Tomatoes and herbs are some of the mostfragile ingredients used in the kitchen and are the canary in the coalmine forindicating when a knife is becoming dull. To test sharpness using a tomato,place the edge of the knife against the skin of the tomato and pullhorizontally with minimal pressure. If the knife bites into the tomato andslices through you know you are sharp. If cutting the tomato requires applyingenough pressure to indent the skin of the tomato, your knife is dull. Freshherbs are also great indicators of sharpness; a sharp knife will produce cleancuts and a dull knife will create bruising at the cut ends of the herbs.

How Sharp is Your Knife?

How did your knives hold up to these sharpness tests? Thebeauty of these sharpness tests is they are free, require little to nopreparation, and easy. You can now always answer the question of whether yourknife is sharp!

Check out the full video below for the entire review ofthese sharpening systems with Kyle and Josh from Work Sharp – and share with uswhat systems you are interested in using or what sharpening solutions youcurrently using to maintain all your knives. Tell us about your experience inthe comments below.