How to Dice an Onion (With Video): The Best Ways to Chop an Onion

Chopping onions only requires a few tools:

1. 1. A chef’s knife. A sharp knife is the key to cutting onions as it will minimize rough tearing of the onion fibers and allow you to chop quickly, both of which will help prevent crying while cutting the onion.
2. 2. A cutting board. Any cutting board will do. (A quick tip: If you find your wooden cutting board smelling like onions even after a soap-and-water wash, try rubbing the board down with coarse salt or baking soda, letting it sit for an hour, and then rinsing and drying.)
3. 3. An onion. Any bulb-forming variety of onion can use the same chopping method: red onions, white onions, sweet onions, and similar types. The only kind of onion that uses a different method of chopping are green onions (also called scallions)—these onions do not form a bulb and therefore cannot be diced in the same way as their bulb-forming relatives. To chop onions, don’t worry about removing the outer layer—the onion skin can be removed much easier during the chopping process.

There are two recommended variations for chopping onions:

1. 1. Crosswise method
2. 2. Lengthwise method

Both methods are very similar, require minimal knife skills, and result in the same finely chopped onions—try out both methods at home to decide which one you prefer.

Try the crosswise method below.

1. 1. Place your unpeeled whole onion on the cutting board. Using your chef’s knife, cut off the ends of the onion: both the stem end and the root end of the onion.
2. 2. Rotate the onion so it’s resting on one of the flat edges from your cuts. Cut the onion in half—your knife should bisect the “bullseye” in the center of the onion. Peel the papery skin off the onion halves and place both halves face-down on the cutting board.
3. 3. Take one half of the onion and make vertical cuts crosswise along it, so that the cut pieces resemble half-moons. As you slice, keep your fingers curled so that your knuckles touch the knife blade and guide the knife—this will prevent you from cutting your fingers.
4. 4. Take a small stack of half-moon pieces and chop perpendicular to their ends, creating small cube-shaped pieces of onion.

Try the lengthwise method below.

1. 1. Place your unpeeled whole onion on the cutting board. Using your chef’s knife, cut off the ends of the onion: both the root end and the stem end of the onion.
2. 2. Rotate the onion so it’s resting on one of the flat edges from your cuts. Cut the onion in half—your knife should bisect the “bullseye” in the center of the onion. Peel the papery skin off the cut halves and place both halves face-down on the cutting board.
3. 3. Take one half of the onion and make deep, thin slices lengthwise along it, but don’t cut all the way to the cutting board—the onion should still retain its shape. As you slice, keep your fingers curled so that your knuckles touch the knife blade and guide the knife—this will prevent you from cutting your fingers.
4. 4. Now cut perpendicular to the lengthwise onion slices. These cuts should go all the way through the onion and result in small, cube-shaped pieces of diced onion.

It’s important to note there is a third method of chopping onions that is popular among professional chefs—but can be dangerous.

• This method calls for making horizontal cuts in a halved onion—meaning the cook slices the onion parallel to the cutting board and toward their hand.
• Then the onion is cut using the crosswise method to give the chef a quickly diced onion.

This method is now not recommended by most home cooks, because it is incredibly easy to slip and cut your fingers. If this has been your preferred method, try out the crosswise method and lengthwise method of chopping onions—they should produce the same results with minimal chance for cutting yourself.

Onions are known for releasing eye-irritating fumes when cut, and home cooks have plenty of “home remedies” for how to cut onions without crying—holding a matchstick between your teeth, wearing glasses, or even keeping the onion in the freezer first. In the end, there isn’t one surefire way to protect yourself from crying, but there are a few reliable ways to minimize tears while chopping onions:

1. 1. Use a sharp chef’s knife. Where a dull or serrated blade will create tons of microtears in the onion’s flesh, a sharp chef’s knife will make the cleanest slice with the fewest rips, minimizing the number of fibers that will react to the cut.
2. 2. Keep the cut sides face-down. Once an onion is cut, it will immediately begin releasing fumes—but keeping the cut sides face-down will prevent the fumes from making contact with the air, helping to reduce the fumes that will reach your eyes.
3. 3. Chop the onion quickly. Working quickly and efficiently is arguably the best way to chop an onion without crying because by minimizing the amount of time you spend over the onion, you minimize your exposure to the eye-irritating fumes. That means that practicing often and using the safest and most efficient method is the best way to slice onions tear-free.

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