Diced onions on a wooden cutting board.
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How to Dice an Onion


Time for a cooking basics lesson. A lot of recipes called for diced or chopped onions. But unless you learned how to properly dice an onion, it can take more time, be less safe, and the onion sizes are all over the place. In this tutorial, I will show you a common method for how to dice an onion.

This is NOT the only method for dicing onions. There are a few variations and people use them depending on who taught them, but they all get the job done.

Let’s get started!


Yellow onion sitting on a cutting board next to a pairing knife and nakiri knife.

In order to properly dice an onion you need a few things:

  • Onion – Of course, you need an onion. This method will work with pretty much any onion. Here in this tutorial, I use a large yellow onion.
  • Knives – If you follow along exactly you will need both a pairing knife and a chef’s knife or in this case I use a Nakiri knife which works amazing with chopping and slicing vegetables.

How to dice an onion properly

Finger pointing to the root end of a large yellow onion.

Each onion will have a stem end and a root end. To make dicing an onion easier, we will keep the root end intact.

Slicing around the stem of a large yellow onion.

Take a pairing knife and cut a divot around the stem end to remove it. Similar to if you are cutting out the top of a tomato or bell pepper. This step is optional, if you are not comfortable with that particular cut, you can just take your chef’s knife and slice the stem end off with a nice straight cut. You just lose a bit of onion that way. Properly the safer method for beginners.

Look at the onion you will notice vertical lines. That is where we want to cut.

Hand cutting a large yellow onion in half.

Grip the onion with a “claw” grip so the knife runs down the knuckles and the fingertips are curled away from the blade.

Slice the onion in half. A little easier and “Safer” method would be to position the onion cut side down and root side up. Then slice the onion straight in half going through the top root end.

Remove the papery outer skin, and then the first thin layer of onion underneath that.

Slicing a peeled onion.

To dice an onion make sure the root end is positioned away from you. Then grip the onion with the “claw” grip, and slice straight down with the knife getting close to the root end but not all the way. Leaving the root end intact makes dicing onions much easier.

NOTESome people will do a horizontal cut or two. They will put their palm flat on the top of the onion half and then slice horizontally toward the root end. But there really is no reason to do that, since the onion is already layered.

Make each slice about 1/4 inch from each other, moving your hand as necessary. The blade should go straight down your knuckles with your fingertips safely curled in and away from it.

Once you get close to the edge stop.

Finish dicing the onion

Hand with Nakiri knife dicing an onion on a wooden cutting board.

Now rotate the onion half so the slits are perpendicular to your knife. Then grip the onion half with the claw grip and move the knife in about a quarter inch from the edge and slice straight down. This creates the first diced onion pieces. Then move the hand and fingers back 1/4 inch and repeat with a nice slice straight down. Repeat until you get near the edge of the root and it is harder to grip.

Cutting the root end of the onion.

Now flip the remaining root end down so it is flat and just cut around the root. This way you waste very little onion. If there are any larger diced pieces of onion you want to slice smaller go ahead and do that. There shouldn’t be too many if you follow this method for dicing an onion.

There you go, super easy, diced onion ready to be used in whatever recipe that you want, like this tater tot breakfast casserole or this yummy potato salad.

Watch those steps in action with this video tutorial!

How to Dice an Onion | Cooking Basics


  1. Thank you for the great tips, they’re super helpful. I’m finally cutting my onions the right way!

  2. I used to do a horizontal cut! Glad, I came across this post, now I know that horizontal cut isn’t necessary to dice an onion!

  3. This is so awesome! I didn’t know cutting an onion could be this fun! I’ll do it this way from now on! Thanks!

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