1. Start with the standard calorie count

The most widely used reference for raw blueberries is USDA FoodData Central: 1 cup of blueberries is about 84 calories. Since 2/3 cup is two-thirds of a cup, the math is simple: 84 x 2/3 = 56 calories.

A practical rule: if you log 2/3 cup of raw blueberries, use 56 calories as your baseline. If your berries are especially large or you overfill the cup, the true number may be slightly higher.

2. Measure the portion the right way

For the cleanest estimate, use a dry measuring cup and level it off instead of heaping the berries. Blueberries are easy to overpour because the gaps between berries make the cup look less full than it is.

If you have a kitchen scale, weigh the berries instead. USDA data lists 1 cup of blueberries at roughly 148 grams, so 2/3 cup is about 99 grams. Weight is usually more accurate than volume for fruits that vary in size.

3. Log the calories based on how you eat them

Raw blueberries are simple: count the berries only. If you add yogurt, granola, syrup, or whipped cream, those calories are separate and can quickly change the total.

Frozen blueberries are often nutritionally similar to fresh if they are unsweetened. Dried blueberries are very different because the water is removed and the calories are much more concentrated, so do not swap them 1:1.

4. Avoid the most common mistakes

The biggest mistake is assuming every blueberry container or handful equals the same calories. A loose handful can be much less than 2/3 cup, while a packed cup can be more.

Another mistake is using data for sweetened, canned, or dried blueberries when you are actually eating fresh fruit. Always check the form of the fruit first.

If you’re tracking meals to support weight loss or better portion control, tools that help you consistently log food and activity can make the process easier. Fitnit can also help you keep workouts accurate with camera-based rep counting and form analysis, which is useful if you’re pairing nutrition tracking with exercise.

Tips

• Use 56 calories as the standard estimate for 2/3 cup of raw blueberries.
• Weigh blueberries when accuracy matters: about 99 grams is a good target for 2/3 cup.
• Only count add-ins like yogurt, sugar, or granola if they’re part of the serving.
• Check whether your blueberries are fresh, frozen, dried, or sweetened before logging them.
• If you’re meal-tracking often, save the portion in your app so you don’t recalculate it every time.