Tomato Conversions and Equivalents

Fresh Tomatoes to Canned and Chopped by Weight and Volume

Basket of tomatoes

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When your recipe calls for a pound or a cup of tomatoes, it's good to know how many you will need before cooking. Several recipes also call for canned tomatoes, and when you only have fresh ones available, it's essential to know the equivalent for various can sizes. Luckily, there are quick and easy methods for converting various forms of tomatoes.

Tomato Equivalents by Weight

There are many tomato varieties available, and they can often be interchanged in recipes. However, tomatoes come in various sizes, so a kitchen scale is invaluable when a recipe calls for tomatoes by weight. If you don't have a scale, this chart will help you determine how many tomatoes to buy or pick from your garden, and an extra tomato or two is a good idea if the ones available seem small. Generally, one serving of tomatoes is equivalent to 1/2 to 1 pound of fresh tomatoes.

Whole Tomatoes Average Weight
1 large tomato just under 1 pound
3 medium-sized globe tomatoes 1 pound
4 large Roma tomatoes 1 pound
8 small plum or Roma tomatoes 1 pound
15 to 20 cherry tomatoes 1 pound

Converting Tomato Weight to Cups

How you process whole tomatoes yields different amounts of the finished product. For instance, you'll need twice as many tomatoes for a purée than is required for the same volume of chopped tomatoes.

Fresh Tomatoes Volume Once Processed
1 pound 1 1/2 cups chopped
1 pound 3 cups puréed
2 1/2 pounds 3 cups chopped and drained
2 1/2 pounds 2 1/2 cups seeded, chopped, and cooked

Canned Tomato Equivalents

Perhaps you made a last-minute decision to cook a dish that calls for canned tomatoes, and you only have fresh tomatoes in the fridge. Or the recipe calls for cups of tomatoes, and you need to use canned. Not to worry because the conversions are relatively simple:

Canned Tomatoes Fresh Tomatoes
1 cup 1 1/2 cups fresh, chopped, cooked
1 (14.5-ounce) can 5 to 6 small tomatoes, or about 1 pound
1 (16-ounce) can 2 cups undrained, 1 cup drained
1 (28-ounce) can 3 cups undrained, 2 1/2 cups drained
1 (35-ounce) can 4 cups undrained, 3 cups drained

Tomato Sauce and Paste Conversions

Fresh tomatoes are very juicy. To make tomato sauce, you'll need to cook off a lot of that liquid, and tomato paste is even more concentrated and thicker. In reverse, if you need to transform tomato sauce or paste into a fresh tomato substitute, you'll need to add water.

1 cup firmly packed chopped fresh tomatoes 1/2 cup tomato sauce plus 1/2 cup water
1 cup tomato sauce

1/2 cup of tomato paste plus 1/2 cup water

Selecting the Best Tomatoes

Today's supermarket and garden options offer several varieties of tomatoes—cherry, grape, yellow, heirloom, vine-ripened, Campari, Kumato, beefsteak, and Roma, to name just a few. But no matter which you pick, it is important that you know what to look for to ensure that you're getting the best quality. There are three ways to determine whether a tomato is worth buying: appearance, feel, and smell. 

First, look for tomatoes that have a deep, bright color. "Vine-ripened" tomatoes may be your best bet since most tomatoes are harvested while still green and left to ripen in transport, resulting in a pale, bland-tasting fruit. Also, check for blemishes such as black spots—they may seem like nothing but could signal that the inside is rotting.

Next, hold the tomato–you want it to feel heavy in the hand. A tomato with a bit of weight is typically ripe and pleasingly juicy inside. Then give it a gentle squeeze. How much give is there? A perfect tomato should have a bit of resistance but not feel rock hard. Of course, you also don't want it to be a pile of mush.

The last step is to take a whiff. If you don't smell anything, you probably won't taste anything. The best options are tomatoes with an earthy, sweet aroma that is somewhat strong. 

Tomatoes packaged in plastic wrap or containers make it impossible to touch or smell them. When you can, avoid buying pre-packaged tomatoes, but if they are your only option, do the best you can.