Watermelon is a summertime favorite, but when you’re tracking protein, it’s easy to assume this juicy fruit is protein-packed. In reality, watermelon is mostly water and contains only about 0.61 grams of protein per 100 grams. This free calculator works out exactly how much protein you’re actually getting from any portion — whether you eat a single wedge, a cup of diced cubes, or an amount measured in ounces.
Just enter the amount of watermelon you plan to eat, choose your unit, and hit calculate. The tool instantly converts your portion to grams, calculates the protein content, and can even show the percentage of your daily protein target. It’s designed for anyone counting macros, following a higher-protein eating plan, or simply curious about the nutritional value of their fruit salad.
Use the quick-fill serving buttons for common estimates, and check the step-by-step breakdown to understand the math behind each result.
🍉 Watermelon Protein Per 100g Calculator
Enter a serving size to estimate protein from raw watermelon.
How This Calculator Works
Watermelon is a refreshing, high-water fruit, but it is not a significant source of protein. According to the USDA FoodData Central database, 100 grams of raw watermelon edible portion contains about 0.61 grams of protein. This calculator applies that density to your chosen serving size using the formula below. Because serving sizes are often given in cups or wedges rather than grams, the calculator first converts your portion to grams using standard kitchen equivalents: 1 cup of diced watermelon weighs about 152 grams, 1 wedge or slice (around 1/16 of a whole melon) weighs about 286 grams, and 1 ounce by weight equals 28.35 grams. Once the serving weight is known, the protein content is calculated proportionally.
Step-by-Step Guide
Enter the amount of watermelon you plan to eat in the amount field, then choose the matching unit from the dropdown: grams, ounces, cups, or slices/wedges. If you want to see how the portion fits into your daily protein intake, switch on the optional daily protein goal checkbox and type your goal in grams. Click Calculate to generate your result, including the exact protein, serving weight, and a breakdown of the math. The Reset button clears the output and restores the defaults. For the most accurate macro tracking, weigh the watermelon flesh (without the rind) on a digital food scale before eating. Cup measurements can vary: larger dice leaves more air gaps, while finely chopped pieces pack more tightly.
Worked Examples
Example 1: 1 cup of diced watermelon. A standard cup of diced watermelon weighs about 152 g. Protein = 152 × 0.61 / 100 = 0.93 g.
Example 2: 1 large wedge. A typical wedge (1/16 melon) weighs about 286 g. Protein = 286 × 0.61 / 100 = 1.74 g.
Example 3: 8 ounces by weight. 8 oz converts to 226.8 g. Protein = 226.8 × 0.61 / 100 = 1.38 g.
Nutritional Reference Values
These values are for raw watermelon, based on USDA FoodData Central. Use them as a reference when planning meals:
| Measure | Approx. Weight | Calories | Protein | Carbs | Fiber |
|---|---|---|---|---|---|
| 100 g | 100 g | 30 kcal | 0.61 g | 7.55 g | 0.4 g |
| 1 cup diced | 152 g | 46 kcal | 0.93 g | 11.5 g | 0.6 g |
| 1 wedge (1/16 melon) | 286 g | 86 kcal | 1.74 g | 21.6 g | 1.1 g |
All figures are rounded. Actual values may vary slightly by variety and ripeness.
Pro Tips for Protein Tracking
- Weigh the raw, edible portion before eating. Rind and seeds should not be included.
- Watermelon is hydrating and low in calories, but it is not a meaningful protein source. Pair it with Greek yogurt, cottage cheese, eggs, or a handful of nuts to balance your snack.
- Track by weight rather than slice size. Wedges vary a lot depending on how the melon is cut.
- If you blend watermelon into smoothies, measure the fruit you actually add rather than guessing by volume.
If you’re comparing protein across foods, check out the edamame protein per 100g calculator or the passion fruit protein calculator for other plant-based examples.
Frequently Asked Questions
Is watermelon a good source of protein? No. Watermelon is about 91% water and contains roughly 0.6 g protein per 100 g. It carries very little protein, though it contributes to hydration and provides some important vitamins and plant compounds.
Does the protein content change with ripeness? Like most fruits, the exact nutrient profile can shift slightly with variety, ripeness, and growing conditions. The 0.61 g per 100 g figure is the standard USDA average for raw watermelon.
Should I count watermelon protein in my macro totals? Yes, every gram counts. A cup of watermelon adds roughly 0.9 g, and a large wedge adds about 1.7 g, so it is easy to include in your daily total.
How can I make my watermelon snack higher in protein? Pair it with cottage cheese, Greek yogurt, grilled chicken in a salad, or a sprinkle of hemp seeds. The sweet, watery fruit acts as a refreshing contrast to richer protein foods.