How to convert ground cinnamon
Our reference is 124.8 grams per US reference cup of ground cinnamon, ground cinnamon, levelled spoon. That works out to about 0.5275 grams per millilitre, so cups = grams ÷ 124.8 and grams = cups × 124.8 in US customary measures.
For metric and Australian recipes the cup holds 250 ml, so one cup of ground cinnamon is about 131.87 grams. Australian tablespoons hold 20 ml rather than 15 ml, which the calculator handles when you pick that system.
Preparation changes the weight
The reference describes ground cinnamon as: ground cinnamon, levelled spoon. A different form, such as sifted, packed, melted, chopped or cooked, can hold a different weight in the same cup and needs its own reference. When a recipe gives a gram amount, weigh that amount instead of converting.
Brand, moisture and how firmly the cup is filled all move the practical result. Treat the numbers here as recipe equivalents, not laboratory densities.
Where the number comes from
The reference comes from USDA FoodData Central (SR Legacy): Spices, cinnamon, ground, which lists 1 teaspoon as 2.6 grams. USDA measured portion of 2.6 g per teaspoon (7.8 g per tablespoon), multiplied by 48 teaspoons per US cup. This site assigns the published cup weight to its adopted US reference cup of 236.5882365 ml; the source itself does not define an exact millilitre cup volume. Checked September 26, 2026.