How Many Calories Are In Cucumbers? | The Low-Cal Truth

You probably know cucumbers are mostly water — but you might not realize just how few calories that translates to. Diet plans often list them as a free vegetable, meaning you can eat them without worrying about your daily energy budget.

A single cup of raw cucumber with the peel still on contains only about 16 calories. That’s less than a bite of an apple. Here’s exactly what you get in each serving size and why cucumbers are a go-to for anyone watching their energy intake.

Calorie Counts By Serving Size

The most common question is simple: how many calories are in a cucumber? The answer depends on how much you eat and whether you leave the peel on.

One cup of raw cucumber slices with the peel (about 104 grams) provides roughly 16 calories. That makes it one of the lowest-calorie vegetables you can add to a salad or snack plate.

A half-cup serving of sliced cucumber delivers around 8 calories, while an entire medium cucumber (around 11 ounces or 300 grams) totals about 45 calories. If you weigh your food, 100 grams of cucumber contains approximately 12 to 15 calories.

Peeling the cucumber reduces the calorie count slightly. A large peeled cucumber contains about 34 calories, compared to 45 for an unpeeled one of similar size. The difference comes mostly from trace carbohydrates in the skin, according to general nutrition data.

Why Cucumbers Are So Low In Calories

Cucumbers are roughly 96 percent water — a trait that directly explains their low calorie content. Most of the weight you eat is water, not energy-dense nutrients. But that doesn’t mean they’re empty.

• Hydration boost: With 96% water content, cucumbers can help relieve dehydration in hot weather or after exercise. The high water volume contributes to feeling full without adding calories.
• Essential vitamins: A half-cup serving provides small amounts of vitamin K and vitamin A, important for blood clotting and vision respectively.
• Potassium source: A large cucumber offers 8% of the Daily Value for potassium, which may help support healthy blood pressure levels.
• Volume eating support: The American Heart Association notes you can eat cups of cucumber and barely reach 100 calories, making it an ideal way to fill your plate without blowing your energy target.
• Digestive aid: Some research suggests cucumbers may help prevent constipation and support weight loss, though more studies are needed to confirm these effects.

This combination of high water volume and trace nutrients makes cucumbers a useful food for hydration-focused diets or low-calorie meal plans, without sacrificing the feeling of fullness.

Nutritional Breakdown Beyond Calories

Beyond their low calorie count, cucumbers offer a simple macronutrient profile. A half-cup of sliced cucumber contains 8 calories, 0.3 grams of protein, 1.9 grams of carbohydrates, and 0.1 grams of fat. The carbs come mostly from natural sugars and a small amount of fiber.

USDA SNAP-Ed’s cucumber guide emphasizes the high water content — check their cucumber water content resource for storage and selection tips.

The peel also contributes a modest amount of vitamin K and fiber. Leaving the peel on means you get slightly more nutrients while gaining only a negligible calorie increase.

Serving Size	Calories	Water Content
1 cup slices with peel (104g)	16	~96%
1/2 cup slices (52g)	8	~96%
Whole medium cucumber (300g)	45	~96%
Large peeled cucumber (approx. 300g)	34	~95%
100 grams	12–15	~96%

The small carbohydrate content means cucumbers fit easily into low-carb or ketogenic eating patterns, though they’re not a significant source of protein or fat.

How Cucumbers Fit Into A Low-Calorie Diet

If you’re counting calories, cucumbers are essentially a free vegetable — you can eat a lot without worrying about your daily budget. Here are practical ways they typically show up in common diet strategies.

1. Snack substitution: Replace chips or crackers with cucumber slices dipped in hummus or Greek yogurt. A full cucumber with dip stays under 60 calories.
2. Volume eating: The American Heart Association points out you can eat cups of cucumber and barely reach 100 calories. Add extra cucumber to salads to increase bulk without adding meaningful energy.
3. Calorie offset: You would need to walk for about 4 minutes to burn off the 16 calories in one cup of cucumber slices. That’s an easy way to think about portion size.
4. Infused water flavor: Cucumber slices in water add subtle flavor without calories, encouraging more fluid intake — useful for hydration goals.
5. Low-carb base: Use cucumber slices as a base for toppings instead of bread or crackers. This works for keto or low-carb diets without adding unwanted carbs.

This flexibility makes cucumbers a staple for anyone managing weight, but it’s wise to pair them with protein or healthy fat for a balanced meal.

Comparing Cucumber Varieties And Peel Effects

Cucumbers come in several common varieties — slicing cucumbers (the standard market type), English (hothouse) cucumbers, and pickling cucumbers. Their calorie counts are nearly identical per weight because all share the same high water content.

NC State Extension provides detailed calorie counts for both peeled and unpeeled servings — see their cucumber calories per cup guide. The main difference is that peeled cucumbers contain slightly fewer calories and less fiber, vitamin K, and vitamin A from the skin.

Storage note: USDA SNAP-Ed recommends keeping cucumbers in the refrigerator in a plastic bag for up to one week. Wrapping them helps retain moisture and prevents spoilage.

Preparation	Calories (per 100g)
Raw with peel	~15
Raw, peeled	~11
English cucumber, with peel	~15

The small calorie difference between peeled and unpeeled cucumber means you can choose based on texture preference or recipe needs without worrying about a major energy impact.

The Bottom Line

Cucumbers are one of the lowest-calorie foods you can eat — a cup of slices delivers barely 16 calories. Their high water content makes them hydrating and filling, though they shouldn’t be your only source of nutrients. For weight management or general hydration, they’re a smart addition to most eating patterns.

If you’re following a specific diet plan, such as keto or a low-potassium protocol for kidney health, a registered dietitian can advise how cucumbers fit into your individual daily limits based on your health profile.