Can Size Conversion Chart for Ingredients in Recipes

You've been looking forward to making grandma's sauce recipe—it's an heirloom, passed down from generation to generation, one that your grandmother cooked and that you are committed to making a part of your family's favorite dishes. But some of the measurements aren't quite making sense—like what is a "no. 10 can"?

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When it comes to modern recipe ingredient lists, we are familiar with the measurements of the ingredient listed, as well as the size of the can when applicable—for example, 1 can (15-ounce) tomato paste. But older recipes might just list a can size—which is not a weight or volume measurement but just a name or number—and little else. This is particularly tricky if you're making grandma's traditional recipe for the first time and you aren't sure how much of an ingredient should be included, or if you are downsizing a recipe meant to feed a crowd and have no idea how to cut a "no. 3 squat" can in half.

Luckily, there is a way to convert these old-fashioned can sizes into something more familiar. 

Can Size Conversion Chart

In the event you run across a recipe that doesn't have the measurements spelled out, consider some generally accepted conversions, both for how much to use and how much to buy of that canned ingredient.

Jar Size Conversion Chart

Jars used in preserving your own fruits and vegetables are considered "canned." If you are looking at an old canning recipe, it may list a jar size. These are a little less confusing than the can sizes as jars come in sizes that already reference volume and weight. While there might now be some fancy jars available, older recipes relied on good-old Mason jars.

Miscellaneous Size Conversions

We all have probably come across a recipe with odd or vague ingredient measurements—or maybe no measurements at all. Use some basic conversions to fill in the blanks.

History of Can Sizes

To find out how many cups in a can are required, it's useful to have a little history of the canning industry. According to the guidebook Canning and How to Use Canned Foods by A.W. Bitting and K.G. Bitting, the National Canners Association (it's now called the Food Products Association) says, while there are (or were) some can sizes considered standard, these measurements aren't based on any unit of volume or other requirements, and might lead to confusion for home cooks.

The Canners Association explained that in assigning the mysterious numbers to cans, the American can industry describes the dimensions of cylindrical cans by two numbers: diameter and height. The guidebook's authors lamented the lack of foresight by the canning industry, saying, "The regular No. 2 can is too large for peas, corn, and beans in amount for the average family to use at one time, and the unused part is not as attractive when reheated. The No. 3 can of tomatoes is likewise an anomaly though the objection is not so strong as for the No. 2. The No. 2½ can was introduced as a compromise on the No. 3, especially for fruits, but recently a better size is being used having the diameter of the No. 2½ but only half the height. After machines have once been built to make and close cans of a certain size, it is difficult to make changes no matter how desirable it may be."