CalMind
Popcorn calories: 31 kcal per cup
Nutrition Facts per 100g (Air-Popped, No Oil)
Popcorn Preparations: Nutrition Comparison (Per 3 Cups Popped)
Popcorn calories: preparation and container size matter
The USDA reference is for air-popped popcorn: 387 calories per 100 grams, or about 31 calories for the cited eight-gram cup. A cup is a volume measure, so the number of cups and how densely they are packed both matter.
How to log a U.S. serving
Microwave popcorn should be logged from its package label, including whether the serving is stated as unpopped kernels, popped cups, or part of a bag. Oil, butter flavoring, sugar, caramel, cheese powder, and kettle-corn coatings are not included in the plain air-popped reference.
When to use another entry
Movie-theater sizes are not standardized across U.S. chains. Use the theater's own nutrition page when it identifies the product and serving; added butter topping and shared tubs should be recorded separately.
Frequently asked questions
How many calories are in one cup of air-popped popcorn?
The cited USDA entry gives about 31 calories for an eight-gram cup of air-popped popcorn.
Can I use that value for microwave popcorn?
Not as an exact value. Use the package label because oil, flavoring, and serving definitions vary.
How should movie-theater popcorn be recorded?
Use the specific theater's nutrition information and include added butter topping when applicable.
Sources, U.S. scope, and fact check
Reference item: USDA FoodData Central, “Snacks, popcorn, air-popped” (FDC ID 167959), at 387 kcal per 100g. USDA’s 8g cup reference is about 31 kcal.
Applicable region: U.S. food-composition and portion reference data. Last fact check: July 24, 2026. Oil, butter, sugar coatings, cheese powder, and theater portions require separate calculation.
Editorial information
Written and edited by
Editor-in-Chief at CalMind. Leads editorial direction and English-language nutrition content.
Editorial disclosure added July 17, 2026. This page is not labeled as professionally reviewed unless a named reviewer and verifiable credential are shown.