Watermelon: calories, protein, vitamins
USDA FoodData Central data, retrieved October 2026 · state: fresh
Watermelon: 30 kcal, 0.6 g protein, 0.2 g fat and 7.6 g carbohydrate per 100 g. A typical portion is 1 slice (300 g): about 90 kcal. Below you will find a table with the share of the daily reference, a comparison with five similar foods and where the numbers come from.
- Good source of vitamin C · 10%
- Low in calories
- Low in fat
| Nutrition | per 100 g | % daily value | portion (300 g) | % daily value |
|---|---|---|---|---|
| Calories | 30 kcal | 2% | 90 kcal | 5% |
| Protein | 0.61 g | 1% | 1.83 g | 4% |
| Fat | 0.15 g | — | 0.45 g | — |
| Carbohydrate | 7.55 g | — | 22.7 g | — |
| Fibre | 0.4 g | 1% | 1.2 g | 4% |
| Sugar(limit) | 6.2 g | 7% | 18.6 g | 21% |
| Saturated fat(limit) | 0.02 g | 0% | 0.05 g | 0% |
| Sodium(limit) | 1 mg | 0% | 3 mg | 0% |
| Vitamin C | 8.1 mg | 10% | 24.3 mg | 29% |
| Copper | 0.04 mg | 5% | 0.13 mg | 14% |
Typical portion: 1 slice, 300 g, about 90 kcal. % daily value is for a reference adult (average of men and women); "limit" marks a daily limit, not a target. "High" starts at 20% per 100 g.
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Calories from a photoThese are general estimates generated from published formulas, not a medical prescription. Not reviewed by a doctor or registered dietitian.
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Every number on this page (calorie targets, macro splits and any suggested meal plan) is produced by formulas (Mifflin-St Jeor for basal metabolic rate, standard activity multipliers) or, for AI-generated meal plans, by a language model applying those same formulas. On meal-plan pages the carbohydrate figure for each meal is calculated by difference: total calories minus protein and fat calories, divided by 4. It is not measured or estimated on its own, so read it as an arithmetic balance and not as an independent nutritional analysis of the dish. None of it is individualized medical or nutritional advice, and none of it has been reviewed by a registered dietitian, physician or other licensed healthcare professional.
Ask your doctor or a registered dietitian what is right for you before starting a new diet, especially if you are pregnant or breastfeeding, have a diagnosed medical condition, take prescription medication, or have a history of disordered eating. If you have kidney disease or another medical condition, ask your clinician before raising protein.
Mealyno never recommends a calorie target below your calculated Basal Metabolic Rate (BMR), the minimum energy your body needs at complete rest. Even the most aggressive weight-loss setting is clamped at that floor.
Calorie and BMR estimates use the Mifflin-St Jeor equation (Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990).
Generated: October 2026
Also searched as: watermelon slice.
About this food: Watermelon
A watermelon slice is mostly rind, so the first logging question is what you actually weighed. The figures on this page are for the red flesh only. If you put a slice with its rind on the scale, a large part of the number is the green and white rind you will not eat, and the entry overcounts. Cut the flesh off and weigh that, or count roughly half of a thick slice as edible.
The 300 g portion is a big, wet slice, and it still lands at 90 kcal, because watermelon is about as light as fruit gets at 30 kcal per 100 g. Protein and fat are close to nothing (0.6 g and 0.2 g per 100 g), so it will not keep you full for long. Pair it with salty cheese such as brynza, a classic late-summer combination in Ukraine, or with bread if it replaces a meal.
In season, from August into September, a ripe fruit sounds hollow when tapped and has a creamy yellow patch where it lay on the ground. A whole melon keeps for days at room temperature, but once cut it belongs in the fridge, covered, and is best eaten within a day or two. Seeds are edible and can be ignored in the log. Watermelon juice and cubes frozen for drinks are the same flesh, just easier to portion.
What it is high and low in
No nutrient in 100 g of watermelon reaches 20% of the daily reference, but it is a good source of vitamin C (10%).
It is low in calories (up to 40 kcal per 100 g) and fat (up to 3 g per 100 g). The rule is the same for every food: "high" means at least 20% of the daily reference in 100 g, "good source" means 10-19%. For protein it takes at least 8 g per 100 g and a fifth of the calories from protein.
How it compares with similar foods
We compared watermelon with the five foods in our table that are closest in composition (Strawberries, Melon (cantaloupe), Lemon, Peach and Grapefruit), per 100 g.
Rank among the six: Protein (1 = most): 6th of 6; Calories (1 = fewest): 2nd of 6; Fibre (1 = most): 6th of 6; Carbohydrate (1 = fewest): 1st of 6. The order is computed from the USDA values, so it moves if the table changes.
| Food | kcal | protein | fat | carbs | fibre |
|---|---|---|---|---|---|
| Watermelon | 30 | 0.6 | 0.2 | 7.6 | 0.4 |
| Strawberries | 32 | 0.7 | 0.3 | 7.7 | 2 |
| Melon (cantaloupe) | 34 | 0.8 | 0.2 | 8.2 | 0.9 |
| Lemon | 29 | 1.1 | 0.3 | 9.3 | 2.8 |
| Peach | 39 | 0.9 | 0.3 | 9.5 | 1.5 |
| Grapefruit | 42 | 0.8 | 0.1 | 10.7 | 1.6 |
All values per 100 g.
Where the numbers come from
The values on this page come from USDA FoodData Central, SR Legacy (entry 167765: "Watermelon, raw"). It is the US government's reference database and its data is public domain (CC0). We retrieved it on October 4, 2026 and show it per 100 g of the food in the stated state (fresh). When USDA reports no value for a vitamin or mineral we write "no data", never zero.
The daily value column compares each amount with a reference adult: the average of the adult male and female values in the US and Canada Dietary Reference Intakes (age 19-30), a 2,000 kcal day and 50 g of protein. Sodium (2300 mg), sugar (90 g of total sugars, the EU reference intake) and saturated fat (22 g, under 10% of calories) are limits, not targets. These are general guides for healthy adults, not medical advice.
The portion weight is a typical size, not a USDA value, so weigh your own portion.
Calorie and nutrient questions
How many calories are in 100 g of watermelon?
30 kcal per 100 g, with 0.6 g protein, 0.2 g fat and 7.6 g carbohydrate. A typical portion (1 slice, 300 g) has about 90 kcal.
How much protein is in watermelon?
100 g has 0.6 g of protein, which is 1% of a 50 g daily reference, and a typical portion (300 g) has 1.8 g. Protein supplies 7% of its calories.
Which vitamins and minerals does watermelon contain?
The most per 100 g, as a share of the daily reference: vitamin C 8.1 mg (10%). Every other tracked vitamin or mineral is under 10% or has no USDA value.