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How to dice an onion uniformly and minimize tears with simple tricks

Dicing an onion evenly makes cooking faster and yields better texture, while minimizing tears keeps the task comfortable. These simple, reliable steps and small tricks help you cut uniformly and reduce irritation using common kitchen tools and a few minutes of prep.

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  1. Step 1: Select and chill the onion

    Choose a firm, medium onion (about 150–200 g) with dry skin for easiest slicing. Chill it in the refrigerator for 15–30 minutes to slow gas release and reduce eye irritation.

    [Illustration: whole yellow onion on a small plate in fridge with thermostat nearby]

  2. Step 2: Trim and halve safely

    Cut off the stem end (not the root) about 1 cm, then slice the onion in half through the root with a sharp chef’s knife. Leaving the root intact holds layers together and makes dicing neater.

    [Illustration: chef knife cutting onion in half through root on cutting board]

  3. Step 3: Peel outer layers

    Remove the papery skin and one thin layer of onion if damaged, keeping the root end intact. A clean surface prevents slipping and ensures straight, consistent cuts.

    [Illustration: hands peeling onion skin while root end remains attached on board]

  4. Step 4: Make horizontal cuts

    Place half onion cut-side down and hold it with fingertips curled back. With the knife nearly parallel to the board, make 1–2 horizontal cuts toward but not through the root, spacing them 6–8 mm apart to control dice size.

    [Illustration: half onion on board with hands holding and knife making horizontal slice near root]

  5. Step 5: Make vertical cuts

    Turn the knife perpendicular and make vertical slices from top to root, spacing cuts 6–8 mm apart for a medium dice. Keep the root end intact to hold strips together and steady the onion.

    [Illustration: onion half with vertical parallel cuts spaced evenly held by knuckles]

  6. Step 6: Cross-cut to dice

    Rotate the onion so the root is to your non-dominant hand and slice across the strips with a rocking motion, cutting 6–8 mm apart to produce uniform cubes. Use steady pressure and let the knife do the work to avoid squashing.

    [Illustration: knife cutting across onion strips producing uniform cubes on board]

  7. Step 7: Finish and clean up

    When you reach the root, remove and discard it, then gently separate any stuck pieces with your fingers or the knife tip. Rinse the board and knife in warm water within 5 minutes to prevent residue and lingering odors.

    [Illustration: bowl of diced onion beside discarded root and running tap water over cutting board]


  • Use a sharp 20–25 cm chef’s knife — it reduces crushing and speeds cutting.
  • Aim for 6–8 mm spacing for a medium dice; 3–4 mm for small dice, 10–12 mm for large.
  • Wear fitted goggles or keep a steady fan blowing across your face if you’re highly sensitive to onion fumes.
  • Cut on a damp paper towel under the board to stop it sliding and increase control.
  • After chopping, place diced onion in an airtight container and refrigerate within 1 hour for freshness.
  • If you prefer fewer tears, cut the onion near an open window or under running cold water for the first cut.

  • Never hold the onion with flat fingertips; tuck knuckles inward to avoid cuts.
  • Do not use a dull knife — it requires more force and increases the risk of slipping or crushing the onion.
  • Avoid leaving onion juices on wooden boards for long; wash promptly to prevent staining and odor retention.
  • Keep knives away from children and always cut on a stable, non-slip surface.

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