Chopped pecans

One US cup of chopped pecans weighs 109 grams. Going the other way, 100 grams is about 0.92 cups.

Also called diced pecans, pecan pieces.

Chopped pecans sit in the milled category not because they are milled but because they pack by scoop the way milled powders and small pieces do. A cup of chopped pecans is what remains after whole pecan halves are broken by knife or food processor into pieces of about a quarter-inch, poured into a measuring cup, and lightly leveled. Both King Arthur Baking and USDA FoodData Central publish a figure for this preparation, and the two agree well.

USDA FoodData Central (FDC 170182, Nuts, pecans) gives 109 grams per cup for chopped pecans, which implies a density of 0.4607 g/mL on the US customary cup of 236.5882365 mL. King Arthur publishes 114 grams for the same preparation, which they list as 'diced' rather than 'chopped' though the two words describe the same knife or food-processor result. That figure implies 0.4818 g/mL. The gap between the two is 4.6%, comfortably inside the 10% tolerance this site applies to milled and packed-piece ingredients, so both figures are accepted and the USDA figure is published as the site's primary value.

Pecans pack slightly differently by shape. Whole pecan halves, poured loose into a cup, weigh less than chopped pieces because the halves stack with larger air gaps: USDA publishes 99 g per cup for halves, King Arthur 105 g per cup for whole. Chopping breaks the pieces into smaller units that fill the space between them more efficiently, and the cup weight rises accordingly. Very fine pieces or ground pecan meal pack tighter still, though the difference between coarse and fine chopped for baking is usually less than the 10% tolerance and does not change the published figure.

This entry is specifically for chopped pecan kernels. It does not cover pecan halves, which pack with more air gaps and weigh less per cup; pecan meal or ground pecans, which is much finer and packs denser (King Arthur gives 80 g per cup for pecan meal); or roasted, salted, or sugared pecans, which change composition and therefore density. Each of those, when sourced, will be a separate entry.

The confidence grade is medium because two independent sources agree within tolerance and both are widely used references, but no third source at a higher tier (a standards body or an independent bench measurement) confirms the figure. High confidence will require a third independent measurement.