How many diced onions in a cup?

Onions are a versatile vegetable used in many savory dishes. When a recipe calls for diced onions, it’s important to know how much one cup of diced onions equals in order to prepare the right amount.

Quick Answer

Generally, 1 cup of diced onion is equivalent to about 1 medium onion or 110 grams.

What Factors Determine How Many Onions Are in a Cup?

Several factors impact how many diced onions are in a cup measurement:

Onion Size

Onions come in different sizes, from small pearl onions to large yellow or white onions. Larger onions will yield more diced onion per cup compared to smaller onions. Here is a rough estimate for how much diced onion different sized onions yield:

Onion Size Cups of Diced Onion
Small (golf ball size) Around 3/4 cup
Medium (baseball size) Around 1 cup
Large (5-6 inches diameter) Around 1 1/4 cups

How Onions Are Diced

The diced onion size also impacts how many onions fit in a cup. Larger diced pieces take up more space, while finely minced onions compact down:

Dice Size Onions per Cup
Large dice (3/4-inch) 1/2 to 3/4 medium onion
Medium dice (1/2-inch) 1 medium onion
Small dice (1/4-inch) 1 to 1 1/4 medium onions
Minced 1 1/4 to 1 1/2 medium onions

Onion Type

The onion variety also impacts yield per cup when diced. Sturdier onion types like yellow, white, and red onions will give you a bit more diced onion per cup compared to soft varieties like Vidalia or Walla Walla sweets.

Exact Cup Measurements

To be more precise than the rough estimates above, here are some exact measurements for how many diced onions are in a cup depending on onion size and dice style:

Onion Size Dice Style Cups (packed)
Small Medium dice 3/4 to 1 cup
Medium Large dice 1 cup
Medium Medium dice Around 1 1/4 cups
Large Small dice Around 1 1/2 cups
Large Minced Around 1 3/4 cups

As you can see, an average medium onion diced to a 1/2-inch size will yield right around 1 cup.

Onions by Weight

For the most consistent results, it’s best to weigh your onions. The average medium onion weighs approximately 110 grams. Here’s how much diced onion you get by weight:

Onion Weight Diced Onion Yield
110g (1 medium onion) 1 cup
230g (2 medium onions) 2 cups
340g (3 medium onions) 3 cups
450g (4 medium onions) 4 cups

As you can see, it comes out almost exactly to 110g per cup of diced onion. Weighing onions takes the guesswork out and will give you a more accurate diced onion yield.

Tips for Dicing Onions

Here are some tips for efficiently and accurately dicing onions:

  • Trim off the root and stem ends of the onion first.
  • Cut the onion in half from root to stem end.
  • Peel off the papery outer layers.
  • Lay each half flat side down on a cutting board.
  • Make horizontal and vertical cuts through the onion to get even dice.
  • Keep dice size uniform for accurate yields.
  • Aim for 1/2-inch squares for a medium dice.
  • When measuring diced onions, lightly pack the cup for best results.

Substituting Onion Powder

In a pinch, you can substitute dried onion powder for fresh diced onion. Use the following conversions:

Fresh Diced Onion Onion Powder
1/4 cup 1 teaspoon
1/2 cup 2 teaspoons
1 cup 1 tablespoon

Keep in mind that onion powder has a more concentrated, pungent flavor than fresh onion. Start with a smaller amount and adjust to taste.

Storing Diced Onions

It’s best to use diced onion right away for maximum flavor. But you can store leftover diced onion in an airtight container in the fridge for 2-3 days. The onion flavor will start to diminish over time.

For longer storage, diced onions can be frozen for up to 3 months. Place diced onions in a single layer on a sheet pan and freeze until solid. Then transfer to freezer bags or containers, removing as much air as possible before sealing. Frozen onions are best used for cooking rather than eating raw.

Uses for Diced Onion

Diced onion is a versatile ingredient and aromatic base for many savory dishes. Here are some ideas for using up a cup of diced onion:

  • Sauté with ground meat, peppers, and spices for tacos or burritos
  • Add to scrambled eggs, omelets, frittatas, or quiche
  • Use in soups, stews, chili, pasta sauce, or casseroles
  • Cook into fried rice or stir fries
  • Mix into burgers, meatballs, or meatloaf
  • Top pizzas, flatbreads, bruschetta
  • Simmer into marinara sauce or pasta salad dressing
  • Caramelize in olive oil with salt and pepper for a savory garnish
  • Pickle in vinegar mixture to top sandwiches, hot dogs, or tacos

Onion Equivalents

When a recipe calls for onions, here are some handy equivalents to remember:

  • 1 medium onion = 1 cup diced = 110 grams
  • 1 large onion = 1 1/4 to 1 1/2 cups diced = 160 grams
  • 1 small onion = 3/4 cup diced = 80 grams
  • 1 bunch green onions = 1/4 to 1/3 cup diced
  • 1 teaspoon onion powder = 1/4 cup diced onion


One cup of diced onion typically equals 1 medium sized onion or around 110 grams. However, factors like onion size, dice style, and onion variety can alter the final yield per cup. For the most accuracy, weigh out onion portions rather than relying solely on cup measurements. Properly stored, diced onions will keep for 2-3 days in the fridge or up to 3 months in the freezer.

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