How to Cut an Onion Like a Pro

How to Cut an Onion Like a Pro

If you've ever found yourself in the kitchen, staring at an onion and wondering how to cut it without shedding tears or ending up with uneven pieces, you're not alone. Cutting an onion might seem like a simple task, but there's an art to it. In this guide, we'll break down the process step by step, so you can confidently dice an onion like a pro. No more watery eyes, no more awkwardly shaped onion bits - just perfect, uniform pieces every time.

Why Cutting Onions Can Be a Tearful Experience

Before we dive into the how-to, let's address the tear-inducing mystery of cutting onions. Onions contain a chemical compound called propanethial S-oxide, which is released when you cut into them. This compound wafts up into the air and, when it meets your eyes, triggers a response that leads to tears. So, how do you minimize this tearful experience while mastering the art of onion cutting? Let's find out.

What You'll Need

Before you embark on your onion-cutting journey, make sure you have the right tools at your disposal:


  • Sharp Knife: A sharp knife is crucial for clean, precise cuts. A dull knife can crush the onion cells, releasing more tear-inducing compounds.
  • Cutting Board: You'll need a stable surface for chopping. A wooden or plastic cutting board works well.
  • Bowl: To collect the diced onion.
  • Paper Towel or Damp Cloth: Keep this nearby to wipe your hands and knife.
  • The Laughing Onion: Click here to learn the only way to completely prevent onion tears with this amazing invention
  • Optional: Onion Goggles or Swimming Goggles: If you're particularly sensitive to onion fumes, consider researching why goggles don't actually work completely to protect your eyes. Check out our blog post here:


  • One Onion: Choose a fresh onion of your preference, whether it's yellow, white, red, or any other variety.

Step 1: Prepping Your Onion

1.1. Choosing the Right Onion

Start by selecting a fresh onion. Look for one that is firm and free of any soft spots or signs of sprouting. The type of onion you choose can influence the flavor of your dish, so pick accordingly. Learn more about the different types of onions here and which onion makes you cry the most here.

1.2. Washing and Peeling

Begin by rinsing the onion under cold running water to remove any dirt or debris. Then, using your sharp knife, trim off both ends of the onion. Next, peel away the outer skin, being careful to leave the inner layers intact.

Step 2: Halving the Onion

2.1. Cutting Lengthwise

Place the prepared onion on your cutting board. Hold it steady with one hand while you use your other hand and the sharp knife to cut it in half lengthwise, from the top (stem end) to the root end. Crucially, leave the root end intact; this will serve as a natural handle, keeping the onion layers together as you chop.

Step 3: Making Horizontal Cuts

3.1. Slicing Horizontally

Now that you have two halves of the onion, pick one half to work with first. Place it flat on the cutting board, with the cut side facing down and the root end facing you. Position your fingers with your knuckles serving as a guide and your fingertips tucked in for safety. Start making horizontal cuts across the onion, ensuring not to cut all the way through. Leave about a quarter of an inch of uncut onion at the root end to hold everything together.

Step 4: Creating Vertical Cuts

4.1. Dicing the Onion

With the horizontal cuts in place, rotate the onion half 90 degrees so that the flat, cut side is facing your knife. Begin making vertical cuts down through the onion. As you proceed, the onion will naturally fall apart into small, evenly-sized pieces. Continue cutting until you reach the root end, and then discard the small remaining piece.

Step 5: Repeat for the Other Half

5.1. Mirror the Process

Now, repeat the same process with the other half of the onion. Begin by slicing horizontally, then rotate and make vertical cuts to achieve uniformly diced onion pieces. Consistency in the size of your diced onions is key for even cooking and flavor distribution in your dishes.

Step 6: Storing or Using Your Diced Onion

6.1. Storage Tips

If you don't plan to use all of your diced onion immediately, store the leftovers in an airtight container in the refrigerator. Diced onions can be a versatile ingredient, suitable for a wide range of recipes, and they will stay fresh for several days when stored properly.

Tips for a Tear-Free Onion Cutting Experience

While you're now equipped with the skills to dice an onion like a pro, let's explore some additional tips to help you avoid those pesky tears:

1. The Laughing Onion: The only 100% effective way to prevent onions from making you cry. Whether you cut, slice or chop onions, The Laughing Onion will prevent onion tears. It's bonus feature is to preserve your produce when it is not in use and stored in the fruit bowl. Click the link to learn more and to hear why everyone is talking about The Laughing Onion. 

2. Chill the Onion: Before cutting, consider chilling the onion in the refrigerator for about 30 minutes. This can reduce the release of sulfuric compounds and make the process less tearful.

3. Use a Sharp Knife: A sharp knife is your best friend when cutting onions. It minimizes cell damage and reduces the release of tear-inducing compounds compared to a dull knife.

4. Cut Under Running Water: An unconventional but effective method is to cut the onion under a gentle stream of running water. This helps wash away the sulfuric compounds as they are released, preventing them from reaching your eyes.

5. Light a Candle: Some cooks find that lighting a candle nearby can help burn off the sulfuric compounds before they irritate your eyes. Unfortunately this is a myth and will not work to prevent onion tears.

6. Ventilation: If you have a range hood or a nearby fan, turn it on to help dissipate the onion fumes away from your face.

7. Research Onion Goggles: These are outdated and not necessary if you have the laughing onion. If you frequently work with onions and are highly sensitive to their fumes, a pair of onion goggles or using swimming goggles may seem like a makeshift solution that can shield your eyes from irritation, however research and thousands of reviews have debunked the myth of onion goggles. 

We wrote a comprehensive blog post on how to stop onion tears when cutting onions here

In Conclusion

Mastering the art of how to cut an onion is an essential skill for any home cook. Onions serve as a fundamental ingredient in countless recipes, imparting their unique flavor and aroma to dishes from various culinary traditions. With the right onion, a sharp knife, and the techniques outlined here, you can confidently prepare onions for your favorite meals.

Say goodbye to tears and uneven onion pieces. Armed with the knowledge of how to select, prep, and cut an onion correctly, you're ready to tackle a wide range of recipes with ease. So, the next time you encounter an onion in your kitchen, you can approach it with confidence and precision, knowing that you've mastered the art of onion cutting. Happy cooking!

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