Track protein from sour and cultured foods with this quick Sour Protein Calculator. It handles plain Greek yogurt, kefir, cottage cheese, sour cream, buttermilk, sauerkraut, and dill pickles. Choose a food, enter your serving size, and you will get an instant protein estimate plus a per-100-gram figure you can use for meal prep, macro tracking, and healthy eating goals.
You can enter grams, ounces, cups, or tablespoons, depending on how you measure your food. Quick-fill buttons set common portions such as 100 g, 1 cup, or ½ cup, and the result box also provides a step-by-step breakdown so you can see the calculation clearly. The reference values come from commonly used USDA data and are meant for everyday nutrition tracking, not medical advice.
🥣 Sour Food & Serving Size
Cup and tablespoon estimates use food-specific weights; grams and ounces are the most precise.
📊 Protein Result
How to Use This Tool
Select a sour food from the dropdown, then enter your serving size in grams, ounces, cups, or tablespoons. The calculator uses the food's protein density to estimate how many grams of protein that serving contains. The result area also shows the protein per 100 grams, which is useful for comparing foods on a common basis.
If you are tracking a specific ingredient such as Greek yogurt, the Greek yogurt protein calculator provides a dedicated estimate for that food. This calculator covers a broader range of cultured, fermented, and acidic foods so you can compare options without opening several pages.
How Protein Content Is Calculated
Each food in the list has a reference protein value expressed in grams per 100 grams. To estimate protein in your serving, the calculator converts your chosen unit to grams, then applies a simple proportion:
Protein (g) = serving weight (g) × protein per 100 g ÷ 100
For volume units, cup weights are needed because a cup of yogurt and a cup of sauerkraut do not weigh the same. For example, one cup of Greek yogurt weighs about 245 g, while one cup of sauerkraut weighs closer to 142 g. The table in the Reference Data section shows these values. Grams and ounces do not require a density conversion, so they are the most precise units when you have a nutrition scale.
Worked Examples
Example 1: Greek yogurt
A 150 g serving of nonfat Greek yogurt at 10.2 g protein per 100 g: 150 × 10.2 ÷ 100 = 15.3 g protein.
Example 2: Kefir by the cup
One cup of kefir is about 244 g. At 3.3 g protein per 100 g: 244 × 3.3 ÷ 100 = 8.1 g protein.
Example 3: Cottage cheese
Half a cup of low-fat cottage cheese weighs about 113 g. At 12.4 g protein per 100 g: 113 × 12.4 ÷ 100 = 14.0 g protein.
Tips & Common Mistakes
- Weigh solid foods whenever possible. Cups are convenient, but the exact weight of a cup can change based on how tightly the food is packed, especially for sauerkraut and cottage cheese.
- Use plain, unflavored products. Flavored yogurts and sweetened kefir often contain added sugar and can have different protein values; check the label if the product is sweetened.
- Don't assume all sour foods are high in protein. Cultured dairy foods like Greek yogurt and cottage cheese are protein-rich, but fermented vegetables like sauerkraut and pickles contribute little protein unless they are part of a larger meal.
- Double-check the fat percentage. Fat-free and low-fat dairy can have slightly higher protein per 100 g than full-fat versions, so the difference matters when portions are large.
- Remember that protein estimates are not exact. Packaged foods vary by brand and production method, so use the tool for planning and compare with the USDA or your product label for precise numbers.
Frequently Asked Questions
Which sour food has the most protein? Low-fat cottage cheese leads the group at about 12.4 g per 100 g, followed by nonfat Greek yogurt at 10.2 g per 100 g. Kefir, buttermilk, and regular yogurt are lower, around 3 to 3.5 g per 100 g.
Can I use this calculator for sourdough bread? This version covers the cultured dairy and fermented vegetables listed above, not baked goods. Sourdough bread has a different protein density because wheat flour contributes most of its protein, so the reference values do not apply.
Why does a cup of sour cream weigh less than a cup of yogurt? Fats are less dense than water, and sour cream has a high fat content, so a cup of sour cream weighs roughly 230 g while a cup of yogurt weighs about 245 g. This is why the calculator includes separate cup weights for each food.
Are the results the same as a nutrition label? They should be close, but brands can vary. For packaged products, check the nutrition label for the exact protein per serving. The calculator uses typical USDA reference values, which are a reliable baseline for unflavored, plain varieties.
Reference Data
| Food | Protein per 100 g | Approx. weight of 1 cup |
|---|---|---|
| Plain Greek yogurt, nonfat | 10.2 g | 245 g |
| Plain yogurt, whole milk | 3.5 g | 245 g |
| Kefir, plain whole milk | 3.3 g | 244 g |
| Cottage cheese, low-fat 1% | 12.4 g | 226 g |
| Sour cream, cultured | 2.4 g | 230 g |
| Buttermilk, cultured low-fat | 3.3 g | 245 g |
| Sauerkraut, canned | 0.9 g | 142 g |
| Dill pickles | 0.7 g | 156 g |
Values are rounded from USDA FoodData Central and are intended for general nutrition tracking. For the most accurate numbers, use a food scale and check the nutrition labels on the specific products you buy. You can browse the official USDA FoodData Central database for raw ingredient data.