Protein per 100 grams is the most reliable way to compare the protein density of whole foods, because serving sizes on labels vary so much. This calculator converts between two common expressions: the protein in one serving and the protein in exactly 100 grams. Whether you are meal-prepping chicken breast, choosing a yogurt, or estimating how much tofu to add to a stir-fry, the result helps you see which foods deliver more protein for the same weight.
Use the mode selector to tell the calculator which value you know. Enter the protein amount and serving weight, optionally scale by servings, and get the per-100g figure plus the per-serving and total protein values. The quick-fill buttons load common foods so you can see how the tool works in one click.
This calculator is useful for anyone tracking macronutrients, following a higher-protein diet, or simply learning to read food labels more accurately.
Why Whole Protein Per 100g Matters
Whole, minimally processed foods contain protein as part of a complex matrix of water, fat, carbohydrate, fiber, and micronutrients. Two foods with identical protein per serving can look very different once you express the same information per 100 grams, because one serving might be 30 grams while another is 200 grams. Normalizing to a 100-gram standard lets you make fair comparisons between foods and between brands.
This is especially useful for athletes and people managing body weight. A higher protein density often means you can reach a protein target with fewer total calories, and whole foods provide satiety and nutrients that isolated protein powders do not. The calculator below gives you the same standardized figure that food scientists and dietitians use when evaluating foods.
How to Use This Tool
- Choose the calculation direction. The default mode assumes you know the protein per serving, such as 25 g in a 150 g salmon fillet.
- Enter the protein value and the serving weight in grams. If you use the second mode, enter the label's protein per 100 g instead.
- If you want the total for more than one portion, set the number of servings. The total protein row updates automatically.
- Click Calculate. The result panel shows the protein per 100 g, the protein per serving, and the total protein for your selected servings.
How the Math Works
The core formula is a simple proportion:
Protein per 100 g = (protein per serving ÷ serving weight in grams) × 100
For example, if a 200 g chicken thigh contains 44 g of protein, then 44 ÷ 200 × 100 = 22 g of protein per 100 g.
The reverse calculation is:
Protein per serving = (protein per 100 g ÷ 100) × serving weight in grams
So if Greek yogurt has 10 g protein per 100 g and you eat a 170 g container, you get 10 ÷ 100 × 170 = 17 g of protein.
Worked Examples
Example 1 — Chicken breast. A cooked 120 g chicken breast has 37 g protein. Per 100 g: 37 ÷ 120 × 100 = 30.8 g. Two servings give 74 g total protein.
Example 2 — Greek yogurt. Your nutrition label says 10 g protein per 100 g, and you plan to eat 170 g. Per serving: 10 ÷ 100 × 170 = 17 g. For a week of five servings, the total is 85 g.
Example 3 — Tofu. A 150 g block of firm tofu contains 27 g protein. Its density is 27 ÷ 150 × 100 = 18 g per 100 g, which makes it comparable to many lean meats when scaled to the same weight.
Reference Table: Typical Protein in Common Whole Foods
| Food | Protein (g / 100 g) | Typical serving |
|---|---|---|
| Chicken breast, cooked, skinless | 31 | 100 g |
| Lean beef, cooked | 29 | 100 g |
| Canned tuna, drained | 25 | 100 g |
| Salmon, cooked | 25 | 100 g |
| Almonds | 21 | 30 g |
| Firm tofu | 18 | 100 g |
| Peanut butter | 25 | 32 g |
| Cottage cheese, 2% | 11 | 113 g |
| Greek yogurt, nonfat | 10 | 170 g |
| Lentils, cooked | 9 | 100 g |
| Chickpeas, cooked | 9 | 100 g |
| Egg, whole | 13 | 50 g |
Values are approximate and based on data from the USDA FoodData Central database. Use your specific product label when available.
Tips & Common Mistakes
- Weigh foods after cooking. Meat loses water as it cooks, so raw and cooked protein-per-100g values are different. Use the state you actually eat: cooked for cooked meats, dry for oats and pasta, cooked for legumes.
- Read the serving size on the label carefully. A serving of yogurt can be 150 g, 170 g, or 200 g depending on the brand. Converting to per 100 g removes that confusion.
- Whole protein per 100 g here means the protein contained in the whole food, not the protein digestibility score. It is a density measurement, not a quality score.
- If you track food by ounces instead of grams, try the protein calories per ounce calculator for a similar calculation in imperial units.
- For mixed foods like smoothies, protein comes from several ingredients. The smoothie protein calculator can help you total the contributions from each ingredient.
- Don't compare dry and cooked versions of the same food as if they were equal. Lentils rise from about 9 g protein per 100 g cooked to roughly 25 g per 100 g dry because water is removed.