How to Dice an Onion, a Step-by-step Photo Tutorial

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Heather says:

As we continue with knife skills, here is a photo tutorial on how to dice an onion. I did swipe some of the pics from the how to slice an onion tutorial, because why reinvent the wheel? It will take practice to pick up speed and unless you’re making an exceedingly fancy dish, a perfectly even dice isn’t critical. As long as the pieces are roughly the same size they will be fine for most applications. Generally the sides of a diced onion are 1/4″ or so. This will determine whether two or three planks* need to be cut.

*We’ll get there, don’t worry.

The right tools help. For this chore I prefer a chef knife1, but a utility knife1 can be used in a pinch. Ready?


Grab the onion, a knife, and a cutting board.

Cut off the tip

Slice the tip off of the onion.

Slice the onion in halfSlice the onion in half, through the root. Use the tips of your fingers to steady the onion.

Peel the onionPeel the top most layer from the onion. If the onion is bruised, sometimes a couple of layers will need to be removed.

Cut the first plankMake the first plank cut. Cut from the tip toward the root about 1/4″ above the cutting board. Do not cut all the way through the root, or the onion will be difficult to keep together.

Second Plank CutMake a second plank cut 1/4″ above the first and add a third, if the onion is large.

SliceGrip the onion with the tips of your fingers, if the knife slips, it will most likely come in contact with fingernails rather than flesh. Slice the onion with even cuts, again being careful to not cut all the way through the root.

Adjust gripTurn the onion, adjust your grip to hold the slices together by gently squeezing with the tip of the pinky and thumb. Begin cutting perpendicular -at a right angle- to the slices made in the previous step.

Perpendicular CutAs these cross-cuts are made, the onion will fall away into an even dice.

Diced OnionPretty neat, huh?


1These are an affiliate link to the knives I use most frequently. They are of decent quality, but I don’t feel the need to obsess over their care as I would if I had the knives I daydream about. Even without care obsession, this set has lasted ten years and the handles and blades are still in good shape, despite my abuse.

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7 thoughts on “How to Dice an Onion, a Step-by-step Photo Tutorial”

  1. I do not risk my fingers at all…I have a mini food processor I got at Walmart for less than $5.00 (Black Friday) and it chops onion perfect. I also use it to make home made baby food. Best $5.00 I ever spent.

      • i agree – i couldn't wait to get a cuisinart when i got married 9 yrs ago, and now that i own one i almost never use it. why? because as much as i hate chopping vegetables, i find that it takes me longer to wash out the cuisinart than it does to chop the onion and whatever else might need chopping. but i suppose that might work well for someone who hates chopping more than i do, or hates washing dishes less 🙂

      • I share your aversion to washing out appliances. Seems I always slice my fingers more and worse when washing food processor blades (mini or otherwise). Knives are much safer for me.

  2. i think my way is quicker…i use a serrated steak knife and proceed as you do in your tutorial except i skip the part where you cut "planks"….the onion is circular in pattern which makes cutting the planks a waste of time. if you just make the perpendicular cuts then slice across you will get the same results plus as you lightly squeeze that onion you won't have layers slipping out. the serrated knife has more teeth so to speak so there is very little slippage there either. of course, each to their own method as onion dicing, chopping, slicing etc.. can be deeply personal. i have a cuisinart too and i have'nt used it much unless i have a really big recipe and a really lot of stuff to chop, slice, and dice!

    • Yours may be quicker, yes, but you do not end up with a nice even dice. I know, because I use that same method often myself when I don't really care about the size/shape of the pieces. Of course, I don't use a serrated steak knife, just a very sharp chef's knife. Serrated knives require a sawing motion, which tears the onions rather than give a nice clean cut.

      If you're looking for pieces of a like size, Heather's method here is a great way to go.


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