How much is 1 medium onion chopped?

When cooking, it can be useful to know how much chopped onion you will get from 1 medium onion. This allows you to accurately plan ingredients and portion sizes for recipes. Here are some quick answers to common questions about the amount of chopped onion in 1 medium onion:

Quick Answers

– 1 medium onion equals approximately 1 cup chopped onion

– The exact amount can vary slightly depending on the size and type of onion

– Most medium onions range from 2.5 – 3.5 inches in diameter

– A medium onion weighs approximately 4-6 ounces

What Size is Considered a Medium Onion?

When it comes to onions, the size categories are:

  • Small – under 2 inches diameter
  • Medium – 2-3 inches diameter
  • Large – over 3 inches diameter

A medium onion generally ranges from 2.5 – 3.5 inches in diameter and weighs approximately 4-6 ounces. Onion sizes can vary though based on the specific type and variety.

Common Types of Medium Onions

  • Yellow onions – 2.5-3 inch diameter
  • White onions – 2.5-3.5 inch diameter
  • Red onions – 2-3 inch diameter
  • Sweet onions – 3-4 inch diameter

As you can see, even within medium onions there is some variance in size depending on the specific type of onion.

How Much is 1 Cup of Chopped Onion?

When chopping a medium onion, you will typically end up with right around 1 cup chopped. Here are some more details on onion cup measurements:

  • 1 small onion = 1/2 cup chopped
  • 1 medium onion = 1 cup chopped
  • 1 large onion = 1 1/2 cups chopped
  • 1 extra large/jumbo onion = 2 cups chopped

These measurements are approximate since onion sizes can vary. But in general, this gives a good estimate of how much chopped onion you will get from different sized onions.

Exact Amounts Can Vary Slightly

When chopping onions, the exact chopped yield can vary slightly depending on these factors:

  • Actual diameter size of the onion
  • Onion variety and density
  • How finely the onion is chopped

An exceptionally small or large medium onion could be slightly under or over 1 cup when chopped. And finely diced onion takes up less space than coarsely chopped onion pieces.

Onion Nutrition Information

Here is the nutrition information for 1 cup of chopped raw onion:

Nutrient Amount
Calories 64
Fat 0.11g
Sodium 12mg
Carbohydrates 15g
Fiber 3g
Sugar 7g
Protein 1.4g

Onions are very low in fat, sodium, and calories. They provide fiber, carbs, vitamin C, and trace amounts of nutrients like folate and calcium.

Benefits of Onions

Some health benefits of onions include:

  • May lower blood pressure and improve heart health
  • Contain antioxidants that reduce inflammation
  • Help regulate blood sugar
  • Provide B vitamins and vitamin C
  • Promote healthy gut bacteria

Overall, onions are highly nutritious and provide many health benefits when included as part of a balanced diet.

How to Store Chopped Onions

Here are some tips for storing chopped onions:

  • Place in an airtight container and refrigerate for 5-7 days max
  • For longer storage, freeze chopped onions for 2-3 months
  • Spread chopped onions out on a plate before refrigerating so they cool faster
  • Store in a single layer with parchment paper between onion layers
  • Wrap tightly in plastic wrap for fridge storage

Onions can pick up odors and flavors from the fridge so keep them sealed. Refrigerate within 2 hours of chopping to maximize freshness.

How to Store Whole Onions

To optimize shelf life of whole onions:

  • Keep whole, unpeeled onions at room temperature
  • Place in a basket or bowl with good air circulation
  • Store in a cool, dark place away from sunlight
  • Avoid putting in sealed plastic bags
  • Whole onions can be stored this way for several weeks to months

Only chop what you need, as chopped onions deteriorate faster than whole onions. Whole onions stored properly will stay fresh for extended periods.

Tips for Cooking With Onions

Here are some useful onion cooking tips:

  • Saute over medium-low to caramelize onions slowly for maximum flavor
  • Add a pinch of salt when sauteing to draw out moisture and prevent burning
  • Cook onions thoroughly when using in dishes containing ground meat
  • Use both the white and green portions of scallions/green onions
  • When adding raw onion to salads, rinse under water first to mellow flavor

Onions complement most savory dishes including sauces, soups, stews, sandwiches, pizza, pasta, and more. Caramelized onions have an intense, sweet flavor.

Selecting Good Onions

When buying onions:

  • Choose firm onions without soft or dark spots
  • Avoid onions with green sprouts or signs of mold
  • Yellow and white onions should have dry, papery skins
  • Red onions should have crisp, bright purplish outer layers
  • Sweet onions like Vidalias have softer skins

Handle onions gently to avoid bruising. Damaged or bruised onion bulbs will deteriorate faster.

Onion Equivalents and Substitutions

Sometimes a recipe will call for onion but you only have shallots or scallions on hand. Here are some handy onion conversion equivalents:

  • 1 medium onion = 1 shallot OR 3 scallions
  • 1/2 medium onion = 2 tablespoons dried minced onion
  • 1 small onion = 2 tablespoons onion powder OR 1/4 cup dehydrated onions

You can also substitute onion powder, onion flakes, or dehydrated onions in a 1:4 ratio for fresh onions. These equivalents are not exact but can work well in a pinch.

When to Use Shallots vs Onions

Shallots have a milder, sweeter flavor compared to onions. Here are tips on when to use each:

  • Onions – Soups, stocks, stews, caramelized onions
  • Shallots – Salads, dressings, sauces, raw applications

Shallots are great raw or gently cooked. Onions stand up better to high heat for sautéing and roasting.

Onion Recipe Ideas

Here are some delicious ways to use up chopped onions:

  • French onion soup – caramelized onions in broth
  • Smothered chicken – chicken braised with onions
  • Onion jam – slowly cooked onions with vinegar and sugar
  • Onion rings – sliced onions fried in batter
  • Breakfast tacos – with onions, eggs, potato
  • Crispy onion toppings – for salads, pasta, pizza

Chopped onions can be cooked or eaten raw. They add great flavor to everything from dips and dressings to main courses and side dishes.

Onion Allergy or Intolerance

Some people may experience adverse reactions to onions, including:

  • Digestive issues like bloating or cramps
  • Heartburn or reflux
  • Headaches or migraines
  • Respiratory irritation

Onion intolerances or allergies are not extremely common but do occur. If onions consistently cause negative effects for you, try avoiding them or look for onion-free recipes.


To recap, one medium onion will produce around 1 cup of chopped onion. Exact amounts may vary slightly, but this conversion provides a helpful benchmark for meal planning and prepping recipes. With proper storage, both chopped and whole onions can be kept on hand for everyday cooking needs.

Onions provide a versatile base ingredient to create all kinds of savory dishes. Their sharp flavor mellows and sweetens when cooked, bringing out the best in soups, stews, sandwiches, salads and more. Keeping onions stocked in the kitchen along with tips on prepping and cooking them helps make home cooking quick, easy and delicious.

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