Bridging the gap between grocery shopping and kitchen prep too often requires excessive guesswork. How many mush­rooms do you need for the 1 cup sliced your recipe calls for? How many cloves are in a table­spoon of minced garlic? Many recipes leave it up to the reader to decode these mysteries, leading to befuddlement at the supermarket and frustration at home.

To clear things up, we tested a variety of common items to determine their yield after being chopped, pureed or otherwise prepared to be used in a recipe.

Our testing revealed many useful rules of thumb. A single medium onion produces 1 cup of chopped onion. To make 1 cup of whipped cream, you’ll need to start with ½ cup of heavy cream. And for every cup of pureed pumpkin, you will need roughly a pound of raw squash.

Of course, some foods are easier to measure at the store than others. It’s simple to know how much you are buying with packaged foods, such as heavy cream and cheeses. But the variability of produce can make this more challenging. To help, we’ve offered weights and visual cues where appropriate and suggest that when in doubt, use the scale.