How many calories are in a cucumber?
A medium cucumber, about 200 g, is roughly 30 kcal. Raw cucumber runs about 15 kcal per 100 g — around 96 per cent water — which makes it one of the few foods where the portion stops mattering. You would have to eat a full kilogram to reach 150 kcal.
Per portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 100 g with skin | ~15 kcal | 0.7 g | 3.6 g | 0.1 g |
| 100 g peeled | ~12 kcal | 0.6 g | 2.2 g | 0.1 g |
| 1 cup sliced (~105 g) | ~16 kcal | 0.7 g | 3.8 g | 0.1 g |
| 1 medium cucumber (~200 g) | ~30 kcal | 1.4 g | 7 g | 0.2 g |
| 1 large English cucumber (~350 g) | ~50 kcal | 2.3 g | 13 g | 0.4 g |
| 300 g sticks (a full snack plate) | ~45 kcal | 2 g | 11 g | 0.3 g |
What changes the number
Almost nothing about the cucumber itself. Persian, English and thick-skinned desi kheera sit within a few kilocalories of each other, and peeling takes off two or three along with most of the modest fibre. Ripeness and size change the total only in proportion to weight.
What changes the number is everything served with it:
- 1 tbsp olive oil in a dressing: about 120 kcal
- 2 tbsp mayonnaise-based dressing: 100 to 180 kcal
- Cucumber raita made with 150 g whole-milk curd: 90 to 120 kcal, or 60 to 70 with low-fat curd
- Kachumber finished with a teaspoon of oil: adds about 45 kcal
- A 100 g scoop of tzatziki: 70 to 120 kcal depending on the yoghurt
- Sweetened gherkins: 30 to 90 kcal per 100 g, mostly added sugar
A plate of cucumber is 30 to 50 kcal. The same plate dressed is 150 to 250. The cooking medium decides this food almost entirely, which is unusual even among vegetables.
Where it fits in a deficit
This is the clearest case of volume eating there is. Appetite responds to the weight and bulk of food, not only its energy, so 400 g of cucumber is a dinner-plate’s worth of chewing and stomach-filling for about 60 kcal — the bottom rung of the calorie density ladder. Used as the bulk half of a plate, it lets you cut a meal’s calories without cutting its size.
Two honest limits. Water-based fullness empties quickly, usually within an hour or two, so cucumber delays appetite rather than settling it. And there is nothing else in it: a whole cucumber carries 1.4 g of protein and about 1 g of fibre, so it belongs next to something protein-dense rather than standing in for a meal. A fruit of similar water content but real fibre, such as guava, holds you considerably longer for more calories.
The “negative calorie” claim
Cucumber tops every negative-calorie food list, on the argument that digesting it costs more energy than it supplies. It does not. The thermic effect of food is roughly 5 to 10 per cent of the energy eaten for carbohydrate, which on a 15 kcal portion is about one kilocalorie. The net stays positive — trivially, but positive.
The practical conclusion survives the myth being wrong, which is why it is worth stating plainly rather than repeating. Whether 100 g of cucumber is 15 kcal or 14 is not a number anyone needs to manage. What makes cucumber useful in a calorie deficit is displacement: it occupies the space, the time and the plate that something at 300 kcal per 100 g would otherwise take. That works because of density, not because of a metabolic loophole — and it is the same reason a bowl of watermelon costs so little, at twice cucumber’s density and still only 30 kcal per 100 g.
Figures are typical values and vary by variety, size and preparation. General information, not medical advice.