Onions come in a variety of sizes, from small pearl onions to large Spanish or Bermuda onions. When a recipe calls for “1 large onion,” it’s referring to the common yellow, white, or red bulb onions found in most grocery stores. The exact size of a large onion can vary, but in general a large onion is around 3-4 inches in diameter and weighs approximately 4-6 ounces.
Determining Large Onion Size
There are a few ways to estimate the size of a large onion:
Look at Produce Sizing Labels
Many grocery stores will label onions with size grades like small, medium, large, extra large, etc. This provides a quick visual cue for identifying different onion sizes. If the store labels an onion as simply “large,” it will likely be in the 3-4 inch diameter range.
Weigh the Onion
As mentioned earlier, a large onion weighs approximately 4-6 ounces. You can weigh your onion on a kitchen scale to get a precise measurement. An onion at the smaller end of the “large” spectrum will be around 4 ounces, while a very large onion could weigh up to 6 ounces or slightly more.
Measure the Diameter
Use a ruler or measuring tape to measure the diameter or width of the onion. A large onion will measure between 3-4 inches in diameter. A 3 inch onion is on the smaller side of large, while a 4 inch onion is an extra large large onion.
Size Equivalents
To provide more context, here are some approximate size equivalents for different onion types:
Yellow, White, Red Bulb Onions
| Small | 2-2.5 inches diameter |
| Medium | 2.5-3 inches |
| Large | 3-4 inches |
| Extra Large | Over 4 inches |
Sweet Onions
| Small | 2-3 inches diameter |
| Medium | 3-4 inches |
| Large | 4-5 inches |
| Extra Large | Over 5 inches |
Pearl Onions
| Small | Under 1/2 inch diameter |
| Medium | 1/2 to 3/4 inch |
| Large | 3/4 to 1 inch |
As you can see, a “large” onion covers a wide range depending on variety, but generally falls in the 3-4 inch range for common bulb onion types.
Volume and Yield of a Large Onion
Now that we’ve determined size, how much onion will you actually get from one large onion?
Approximate Volume
A large onion that is 3-4 inches in diameter will have an approximate volume of:
– 1/2 to 3/4 cup chopped
– 1/4 to 1/2 cup diced
– 2 to 4 tablespoons minced
This can vary slightly based on onion variety and moisture content.
Yield When Cooked
When cooked, a large onion will reduce down and yield approximately:
– 1/3 to 1/2 cup cooked chopped onion
– 3 to 4 tablespoons cooked minced onion
Again, moisture loss during cooking can affect yield. But in general, expect a cooked large onion to result in around 1/3 to 1/2 cup chopped onion.
Substituting Onion Sizes in Recipes
In some cases, you may need to substitute a different sized onion than what’s called for in a recipe. Here are some tips:
– Use 2 medium onions instead of 1 large
– Replace 1 large onion with 1 extra large onion if a bolded onion flavor is desired
– Substitute 2-3 small onions when a large onion is unavailable
– Adjust cooking time as needed for differing onion sizes
The important thing is maintaining approximately the same volume of onion, even if the diameter of the onions varies.
Storing Large Onions
To maximize freshness and shelf life:
– Store unpeeled, whole onions in a cool, dry, well-ventilated area. Avoid excessive moisture.
– Whole onions will last 2-4 weeks when stored properly.
– Cut onions can be refrigerated in a sealed container for 7-10 days. Utilize within 2 weeks for best quality.
With proper storage, a large onion can be enjoyed for several weeks before beginning to deteriorate in quality and flavor.
Conclusion
A large onion generally ranges from 3-4 inches in diameter and provides around 1/3 to 1/2 cup cooked chopped onion. Look for produce size labels, weigh the onion, or measure diameter to determine if your onion qualifies as large. Adjust recipe onion amounts if substituting a different size. Store whole, unpeeled onions in a cool, dry area for optimal shelf life. Now that you know what constitutes a large onion and how much yield to expect, you can shop for and select the perfect large onion for your recipes!