How many calories are in a potato?
A medium boiled potato — about 170 g (6 oz) — comes to roughly 140 kcal. Plain potato runs around 85 kcal per 100 g boiled, which puts it in the same density band as fruit and pulses, well below bread, pasta or rice.
Per portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| One medium potato, boiled (170 g / 6 oz) | ~140 kcal | 3 g | 32 g | 0 g |
| 100 g (3.5 oz) boiled, skin on | ~85 kcal | 2 g | 20 g | 0 g |
| 100 g baked in its skin | ~95 kcal | 2.5 g | 21 g | 0 g |
| One large jacket potato (280 g / 10 oz), plain | ~260 kcal | 7 g | 58 g | 0.5 g |
| 200 g (7 oz) mash made with milk and butter | ~230 kcal | 4 g | 30 g | 9 g |
| 150 g (5 oz) chips, a medium takeaway portion | ~450 kcal | 5 g | 55 g | 22 g |
| 30 g (1 oz) crisps, a small bag | ~160 kcal | 2 g | 15 g | 10 g |
Same vegetable in every row. The spread — 85 to over 500 kcal per 100 g — is almost entirely what it was cooked in.
What changes the number
The cooking medium, first and by a long way. Boiling and steaming add nothing at all. Baking adds nothing either; a baked potato reads a little higher per 100 g only because water has evaporated and each remaining gram is more concentrated. Oil is where the calories arrive. A tablespoon is about 120 kcal, and potatoes absorb it in proportion to surface area, so thin-cut chips and crisps run far higher than thick wedges of identical weight.
What goes on top. On a jacket potato the filling routinely outweighs the potato: 20 g (0.7 oz) of butter is about 150 kcal, 30 g (1 oz) of grated cheddar about 120 kcal, two tablespoons of soured cream about 60 kcal. A 260 kcal jacket can leave the kitchen past 550.
Variety and size, barely. Floury and waxy types differ by perhaps 10 kcal per 100 g, waxy slightly lower because it holds more water. New potatoes are marginally lower again. Size matters more: a “medium” potato in practice runs 150–250 g (5–9 oz), so the honest range for one potato is 125–210 kcal.
Where it fits in a deficit
Boiled potatoes are among the most filling foods per calorie that anyone has measured. In satiety testing they sit at or near the top of the list, ahead of bread, rice and pasta — bulk, water and plain starch seem to register as a meal in a way that denser carbohydrate does not. A 400 g (14 oz) plate of boiled new potatoes is a large serving for about 340 kcal, which is the arithmetic that makes a calorie deficit tolerable, and why potatoes head every list of high-volume foods.
What they are not is a protein source: about 2 g per 100 g. A potato-based meal needs eggs, fish, dairy or pulses alongside it to keep protein where it should be.
For comparison, a sweet potato of the same weight is not lower — it is fractionally higher — and the ~180 kcal in two medium slices of bread buys you much less plate than 200 g of potato does.
The honest caveat is not about the potato. It is that potato is the food most often used as a vehicle for fat, and the vehicle is cheap while the fat is not.
The cold-potato claim
Cooking a potato and then cooling it converts some of its starch to resistant starch, which is less completely digested. The effect is real and it is small: a few per cent of the available energy, not the third often claimed. Chilled potato is a meaningfully gentler choice for blood glucose and roughly the same choice for calories.
In practice it is self-defeating anyway: cold potato usually arrives as potato salad. One tablespoon of mayonnaise is about 95 kcal — more than the resistant starch saves across a whole bowl.
Figures are typical values and vary by variety, size and preparation. General information, not medical advice.