How Many Calories in a Small Tomato? (18 Calories)

A small tomato (approximately 100 grams or 3.5 ounces) contains just 18 calories, making it an excellent low-calorie addition to any diet. This nutritional fact is verified by the USDA FoodData Central database, the most authoritative source for food composition information.

Discover exactly how many calories are in a small tomato and why this vibrant fruit deserves a permanent spot in your healthy eating plan. Whether you're tracking macros, managing weight, or simply curious about nutrition, understanding the precise caloric value of everyday foods helps you make informed dietary choices without sacrificing flavor or nutrition.

What Exactly Qualifies as a Small Tomato?

Before we dive into calorie counts, it's crucial to define what "small" means in tomato terminology. Many people don't realize that tomato sizes vary significantly across varieties, which directly impacts nutritional calculations.

Tomato Size	Weight (grams)	Calories	Common Varieties
Small	80-100g	14-18	Roma, Grape, Campari
Medium	100-150g	18-27	Roma, Beefsteak
Large	150-200g	27-36	Beefsteak, Heirloom

According to the USDA's standardized measurements, a "small" tomato typically refers to varieties like Roma or Campari tomatoes weighing approximately 100 grams (3.5 ounces). This precise definition matters because many nutrition apps and websites use inconsistent sizing standards that can lead to inaccurate calorie tracking.

Why Tomato Size Matters for Calorie Counting

When tracking your daily calorie intake, even small discrepancies can add up. Consider this real-world scenario: if you're using an app that assumes all "small" tomatoes contain 25 calories (an inflated estimate), you could be overestimating your intake by nearly 40%.

The USDA FoodData Central database (accessed September 2025) provides the most reliable measurements for food composition. Their testing methodology involves analyzing multiple samples from various growing regions to establish accurate averages. This scientific approach ensures the 18-calorie figure for a 100g tomato represents a trustworthy standard you can rely on for precise nutrition tracking.

Complete Nutritional Profile of a Small Tomato

While calories are important, tomatoes offer remarkable nutritional value beyond just their low energy content. A single small tomato (100g) provides:

• Carbohydrates: 3.9g (1.2g fiber, 2.6g sugar)
• Protein: 0.9g
• Fat: 0.2g
• Vitamin C: 14mg (23% of daily value)
• Vitamin A: 833IU (17% of daily value)
• Potassium: 237mg (7% of daily value)
• Lycopene: 2573mcg (powerful antioxidant)

What makes tomatoes particularly valuable is their exceptional nutrient density—packing significant vitamins and antioxidants while contributing minimal calories to your daily intake. The lycopene content, responsible for tomatoes' red color, increases when tomatoes are cooked, making both raw and cooked preparations nutritionally beneficial in different ways.

How Tomatoes Fit Into Different Dietary Approaches

Whether you're following a specific eating plan or simply aiming for balanced nutrition, small tomatoes adapt beautifully to various dietary frameworks:

Weight Management

With only 18 calories per small tomato, they provide volume and satisfaction without significant caloric cost. Registered dietitians often recommend including tomatoes in weight loss plans because their high water content (95%) and fiber promote fullness.

Keto and Low-Carb Diets

While tomatoes contain carbohydrates, a small tomato's 3.9g total carbs (with 1.2g fiber) results in just 2.7g net carbs—easily accommodated within most keto frameworks when portion-controlled.

Mediterranean and Heart-Healthy Diets

The potassium and lycopene in tomatoes support cardiovascular health. Multiple studies, including research published in the American Journal of Clinical Nutrition, associate regular tomato consumption with reduced risk of heart disease.

Practical Tips for Maximizing Tomato Nutrition

Understanding calories is just the beginning. Here's how to get the most nutritional value from your tomatoes:

• Pair with healthy fats: Lycopene absorption increases by 2.5x when tomatoes are consumed with olive oil or avocado
• Store properly: Keep tomatoes at room temperature away from direct sunlight to preserve flavor and nutrients
• Vary your preparations: Raw tomatoes provide more vitamin C, while cooked tomatoes offer higher lycopene bioavailability
• Track accurately: Use kitchen scales for precise measurement rather than estimating by count

Common Misconceptions About Tomato Calories

Several myths persist about tomato nutrition that can lead to inaccurate dietary planning:

• "All tomatoes have the same calorie count" - Different varieties and ripeness levels affect water content and thus calorie density
• "Cooked tomatoes have more calories" - Cooking concentrates flavor but doesn't increase calories; it may actually reduce them slightly through water loss
• "Cherry tomatoes are higher in sugar" - While slightly sweeter, cherry tomatoes have similar calorie density per gram as larger varieties

These distinctions matter for precise nutrition tracking. The USDA database accounts for these variations through rigorous testing protocols that analyze multiple samples across different growing conditions and seasons.

How many calories in a small Roma tomato?

A small Roma tomato weighing approximately 100 grams contains 18 calories according to USDA FoodData Central. Roma tomatoes are slightly denser than other varieties but maintain similar calorie counts per weight measurement.

Do cherry tomatoes have more calories than regular small tomatoes?

Cherry tomatoes have similar calorie density per gram (about 0.18 calories per gram). A single cherry tomato (12-15g) contains 2-3 calories, while a small regular tomato (100g) contains 18 calories. The difference is in portion size, not calorie density.

Are tomatoes good for weight loss?

Yes, tomatoes are excellent for weight loss due to their low calorie density (18 calories per 100g), high water content (95%), and fiber content. They provide volume and satisfaction with minimal calories, helping create a calorie deficit while maintaining nutrition.

How many small tomatoes can I eat for 100 calories?

Since one small tomato (100g) contains approximately 18 calories, you could eat about 5-6 small tomatoes to reach 100 calories. This would provide nearly 500 grams of food volume while staying within your calorie goals.

Does the calorie count change if I cook small tomatoes?

Cooking doesn't significantly change the calorie count of tomatoes. While water loss concentrates flavors, the actual caloric value per 100g remains similar. However, cooking increases lycopene bioavailability, making nutrients more accessible to your body.