Ground Cinnamon

One US cup of ground cinnamon weighs between 96 and 154 grams, depending on how the cup is filled and which source measured it. That range is the answer; a single number would not be. Every figure behind it is below, with the method each source used.

Also called ground cinnamon, cinnamon powder, cinnamon ground, cassia cinnamon ground, ceylon cinnamon ground, true cinnamon ground, saigon cinnamon ground, vietnamese cinnamon ground, chinese cinnamon ground.

TL;DR: 96-154 g/cup (0.41-0.65 g/mL). Fine bark powder with wide packing variance across brands and grinds. USDA reference at 119 g/cup (0.50 g/mL) is the central working figure; brand-to-brand spread of 60% is normal for fine light spices where scoop technique matters more than for granulated ingredients.

Ground cinnamon is the inner bark of Cinnamomum trees, dried and milled to a fine reddish-brown powder. Two botanical types dominate global commerce: cassia cinnamon (Cinnamomum cassia and its close cousins C. burmannii Indonesian, C. loureiroi Vietnamese/Saigon, C. cassia Chinese) makes up about 95% of the US market and delivers the strong, sweet-spicy flavor most Americans associate with cinnamon rolls and pumpkin pie. Ceylon cinnamon (Cinnamomum verum, marketed as "true cinnamon") is milder and more delicate, standard in Latin American and European baking, and preferred by some households for its dramatically lower coumarin content. Both types grind to nearly identical bulk density; the choice between them is a flavor and health decision, not a measurement one.

Density data spans a wide 60% range that reflects real packing behavior rather than product quality. USDA FoodData Central SR Legacy (FDC 2010) gives 119 g per US cup at 0.50 g/mL — the canonical reference used by conversion sites and cookbook authors when no brand-specific density is available. USDA branded entries via aqua-calc scatter across the range: UPC 855269003480 at 96 g/cup (lighter than USDA reference), UPC 011216287109 at 115 g/cup (near USDA), UPC 016291441132 at 154 g/cup (about 30% above USDA). The eatthismuch aggregate across McCormick, Great Value, Kirkland Saigon, Simply Organic Ceylon, and Stonemill reports 3 g per teaspoon, extrapolating to 144 g/cup — near the high end. McCormick's own 4.12 oz product label lists 1/4 tsp = 0.4 g, which extrapolates to 77 g/cup, but this figure is almost certainly an FDA-rounded label serving (0.4 g rounds to zero calories, which is what the label declares) and not a physical density measurement. King Arthur's Ingredient Weight Chart is silent on plain ground cinnamon; it lists Cinnamon Sweet Bits, Cinnamon-Sugar, and Baker's Cinnamon Filling but not the base spice.

The 60% brand spread comes from three factors that all matter more for fine light powders than for granulated ingredients. First, grind fineness: some brands mill to a very fine dust that packs down denser (Saigon cassia products from McCormick and Kirkland tend heavier), while others grind coarser (small-batch Ceylon products tend lighter). Second, moisture content: cinnamon is hygroscopic and absorbs ambient humidity, so a jar opened in a humid kitchen weighs more per cup than the same brand tested in dry lab conditions. Third, scoop technique: pressing a measuring spoon into the jar packs the powder about 20% denser than lightly spooning it. USDA reference conditions are spooned-and-leveled, which is the standard baking assumption.

For a recipe calling for "1 teaspoon ground cinnamon," the practical difference between 2 g (light scoop) and 3 g (packed scoop) is unlikely to affect the outcome — most baking recipes use cinnamon at 0.1-1% of flour weight where a 50% variance in the spice weight is well within taste tolerance. Where the difference matters is in high-cinnamon-content applications like snickerdoodle coatings, cinnamon-sugar toppings, or spice-heavy chai blends: weigh out the intended quantity rather than relying on the volume conversion, especially when switching between a densely-packed jar (Saigon cassia) and a lighter one (Ceylon).

On the two-species question: cassia and Ceylon are not interchangeable in a health-conscious kitchen. Cassia contains 5-12 mg/g of coumarin, a compound linked to liver stress in high doses; the European Food Safety Authority sets a Tolerable Daily Intake of 0.1 mg/kg body weight, which a 70 kg adult reaches at roughly 1 teaspoon of cassia per day (2 g times 8 mg/g averages to 16 mg, about 2x TDI). Ceylon contains 0.01-0.1 mg/g coumarin, roughly 100-1000x lower. In flavor: cassia is bolder and more assertive; Ceylon is subtler and more citrusy. In price: Ceylon runs 3-6x the cost of cassia. Most US grocery cinnamon is unlabeled cassia by default; Ceylon is typically labeled prominently as such.