Watercress is one of the most nutrient-dense leafy greens you can add to your plate, yet it is rarely counted in a high-protein eating plan. This watercress protein calculator converts any serving size — grams, ounces, chopped cups, or handfuls — into the exact grams of protein it provides, along with the calories from protein and its share of your daily protein target.
Whether you are meal-prepping salads, building green smoothies, tracking macros, or simply curious how this peppery green stacks up against other vegetables, this tool gives you a quick, evidence-based answer. Just enter your portion, choose the unit, and hit calculate. You will also see the step-by-step math so you understand exactly how the protein figure was derived.
All calculations use standard USDA nutrition data for raw watercress, so you can rely on it for consistent meal planning and macro tracking.
🥬 Watercress Protein Calculator
Find the protein in any serving of raw watercress — by grams, ounces, cups, handfuls or bunches.
Serving size
⚙️ Daily protein target
Step-by-Step Guide
This calculator is designed for quick, accurate macro estimates. Start by entering the number that matches how you usually measure watercress — as a weight in grams or ounces, or as a volume in chopped US cups. You can also use handfuls or bunches when you are estimating a portion without a scale.
- Type the size of your watercress portion into the amount box.
- Choose the matching unit from the dropdown menu.
- Optional: tick the daily protein target box and enter your target in grams per day to see what percentage of your goal this serving provides.
- Click Calculate protein to display the protein grams, calories from protein, total calories, and the protein share of calories.
Example: You want a 1.5-cup watercress side salad. Enter 1.5, choose cups, and calculate. The serving weighs about 51 g, provides about 1.17 g protein, and contributes roughly 6 kcal. If your daily target is 60 g, this is about 2% of your goal.
How the Calculation Works
The calculator uses USDA FoodData Central values for raw watercress: 2.3 g of protein and 11 kcal per 100 g. The maths follows three simple steps. First, convert the portion to grams using a standard equivalent for each unit. Second, multiply the gram weight by 0.023 to get the protein content. Third, multiply the gram weight by 0.11 to get total calories, and multiply the protein by 4 to estimate calories coming from protein.
- 1 ounce = 28.35 g
- 1 chopped US cup = about 34 g
- 1 handful = about 25 g
- 1 bunch = about 100 g
For example, a 140 g bag of watercress contains 140 × 0.023 = 3.22 g of protein and about 15.4 kcal. The protein calories total 3.22 × 4 = 12.9 kcal, which shows why watercress is a low-calorie, protein-lean vegetable.
Watercress is roughly 95% water by weight, so a large handful of leaves delivers only a small amount of protein. That is normal for leafy greens and why they are usually paired with protein-rich foods.
Worked Examples
Example 1: 100 g reference serving
A 100 g portion of raw watercress — about three cups — provides 2.3 g of protein and 11 kcal. Protein calories are 9.2 kcal, so protein represents about 84% of the calorie total.
Example 2: Two chopped cups
Two chopped US cups weigh about 68 g. The protein content is 68 × 0.023 = 1.56 g, with total calories of about 7.5 kcal.
Example 3: Half a bunch
If a bunch is roughly 100 g, half a bunch weighs about 50 g and gives 50 × 0.023 = 1.15 g of protein — about 6 kcal.
Nutrition Reference: Watercress vs Other Leafy Greens
The table below compares average raw values per 100 g. Watercress stands out for its very low calorie count while still offering a reasonable protein-to-calorie ratio.
| Vegetable (raw) | Protein (g per 100 g) | Calories (kcal per 100 g) |
|---|---|---|
| Watercress | 2.3 | 11 |
| Spinach | 2.9 | 23 |
| Kale | 2.9 | 35 |
| Arugula | 2.6 | 25 |
| Romaine lettuce | 1.2 | 17 |
Values are approximate and may vary by variety, growing conditions, and measurement method.
Tips & Best Practices
- For the most accurate result, weigh watercress in grams on a digital kitchen scale. Chopped volume can vary depending on how tightly the leaves are packed.
- Use the raw setting value for raw watercress. Cooking changes the water content, so a cooked 100 g portion will contain less water and relatively more protein per 100 g.
- Treat watercress as a nutrient booster rather than a primary protein source. Pair it with eggs, grilled chicken, chickpeas, tofu, or feta for a more balanced salad.
- If you enjoy tracking macros for other greens, you can compare this result with the kale protein calculator or check protein density across more foods with the protein calorie calculator.
- Remember that 30 g of watercress is often enough for a sandwich garnish, while a main salad may use 80–140 g.
Frequently Asked Questions
How much protein is in one cup of watercress?
A chopped US cup weighs about 34 g, so it contains roughly 0.78 g of protein and fewer than 4 kcal.
Is watercress a high-protein food?
For a leafy green, watercress is respectable: 2.3 g per 100 g is more than many lettuce varieties. However, it is still low compared with legumes, dairy, eggs, or meat. It is best used to add volume, vitamins, and antioxidants to a meal that already contains a solid protein source.
Does cooking change the protein content of watercress?
Heat does not destroy the protein. Cooking mainly removes water, which means a cooked portion weighs less but has a higher protein concentration per 100 g. The total protein in the original leaves stays approximately the same.
Why does the calculator show such a high protein percentage of calories?
Watercress has only trace carbohydrate and fat, so protein makes up a large share of its 11 kcal per 100 g. This does not mean it is a high-protein food in absolute terms; it simply has very few non-protein calories.