How many calories in a sweet potato? Size, skin, and the bake-versus-boil swing
Sweet potato calories by size, cooking method, and serving style. Why a baked one tastes denser than a boiled one, and how to log them honestly.
Sweet potatoes are the food people put on a "good carb" list and then accidentally eat 600 calories of in one sitting. The math is friendly when you weigh them and ruthless when you do not. Here is the actual calorie picture, by size, by cooking method, and by what ends up on top.
The quick answer
100g of raw sweet potato is about 86 kcal, with 20g carbs, 2g protein, 3g fiber, and almost no fat. The USDA FoodData Central anchor puts the calorie density at 0.86 kcal per gram raw, which is one of the lowest of any starchy food.
| Portion (raw, with skin) | Weight | Calories | Carbs | Fiber |
|---|---|---|---|---|
| Small | 90g | 77 | 18g | 3g |
| Medium (anchor) | 130g | 112 | 26g | 4g |
| Large | 180g | 155 | 36g | 6g |
| "Big one from the bin" | 250g | 215 | 50g | 8g |
| Per 100g raw | 100g | 86 | 20g | 3g |
Cooking method changes the per-100g number
The total calories of one potato do not change when you cook it. The calories per 100g of the cooked food do, because water moves in or out of the flesh. This is where most logging errors creep in.
| Cooking method | Per 100g cooked | What happens |
|---|---|---|
| Raw | 86 kcal | Baseline |
| Boiled | 76 kcal | Absorbs water, slightly less dense |
| Steamed | 80 kcal | Similar to boiled |
| Baked (with skin) | 105 kcal | Loses water, gets denser |
| Microwaved | 90 kcal | Holds water better than oven baking |
| Roasted in oil (1 tsp per 100g) | 145 kcal | Cooked density plus the oil |
| Mashed with butter and milk | 130 kcal | Roughly per 100g of finished mash |
The honest move is to weigh the sweet potato raw and log it raw, then cook however you like. The single number stays right.
If you only have it cooked, weigh the cooked food and use the cooked density above. (For why this matters more than people think, see portion sizes without a scale.)
Sweet potato vs white potato
The "sweet is healthier" line is overstated. They are close cousins with different vitamin profiles.
| Per 100g raw | Sweet potato | White potato |
|---|---|---|
| Calories | 86 | 77 |
| Carbs | 20g | 17g |
| Sugar | 4.2g | 0.8g |
| Fiber | 3g | 2g |
| Protein | 1.6g | 2g |
| Vitamin A | 14,200 IU | 0 IU |
| Potassium | 337mg | 425mg |
| Vitamin C | 2.4mg | 19.7mg |
Sweet potatoes win on vitamin A and beta-carotene by a margin so wide it is almost a different food category. White potatoes win on potassium and vitamin C. Calorically they are nearly the same.
The carbs vs fat in a calorie deficit post covers why the calorie math matters more than which "type" of carb. Both potatoes can be in a deficit. Both can also break one.
What toppings actually cost
A naked baked sweet potato is one of the more satiating 175 kcal foods you can eat. Most people do not eat it naked.
| Topping | Calories added | Notes |
|---|---|---|
| 1 tsp butter | 35 | Classic, fine in a deficit |
| 1 tbsp butter | 100 | The "diner" amount |
| 1 tbsp brown sugar | 50 | Pure sugar, melts in |
| 2 tbsp marshmallow fluff | 80 | Holiday casserole territory |
| 1 tbsp olive oil drizzle | 120 | Roasted potatoes after the oven |
| 30g feta crumbles | 80 | The savory version |
| 2 tbsp Greek yogurt | 20 | Replaces sour cream cleanly |
| 1 tbsp tahini | 90 | Middle-Eastern style topping |
| 1 tbsp maple syrup | 50 | Brunch finish |
| 30g shredded cheddar | 115 | Loaded baked potato style |
Two tablespoons of butter, brown sugar, and a marshmallow scoop is the difference between a 175 kcal side and a 450 kcal dessert. Same potato.
Sweet potato fries: the trap
Sweet potato fries have the "healthy halo" but cook in deep fryer oil at most restaurants. The fries themselves absorb the oil and end up at a density closer to a doughnut than a potato.
| Form | Per 100g | Per 170g (medium portion) |
|---|---|---|
| Restaurant deep-fried | 235 kcal | 400 kcal |
| Frozen, oven-baked from package | 175 kcal | 295 kcal |
| Air-fried at home, 1 tbsp oil per 200g | 130 kcal | 220 kcal |
| Oven-roasted with 1 tsp oil per 200g | 110 kcal | 185 kcal |
A "small" side at a chain burger spot is usually 250 to 280g, not 170g, which pushes the deep-fried version over 600 kcal. (For why the menu number is often optimistic, reading nutrition labels covers chain restaurant disclosure rules.)
How to log sweet potato honestly
The two-rule version:
- Weigh raw with skin if you can. It is the cleanest number. 86 kcal per 100g raw, every time.
- Pick the right cooked density if you cannot. Baked is denser than raw. Boiled is lighter. Roasted in oil is the raw density plus the oil calories.
The eye-calibration version, when no scale is around:
- A medium baked sweet potato is roughly the size of a deck of cards plus half another. About 175 kcal.
- A "loaded" baked sweet potato (butter, cheese, sour cream) is 350 to 500 kcal.
- One cup of mashed sweet potato is 250g, about 215 kcal plain.
- A diner side of sweet potato fries is 400 to 600 kcal.
What sweet potato is actually great for
Past the calorie panel, sweet potato earns a place in most rotations because of three things:
- Vitamin A density. One medium baked sweet potato delivers about 400% of the daily value. There is no other common food that does this.
- Fiber per calorie. Three to four grams of fiber per medium potato puts it in the upper bracket of starchy foods. (See how much fiber per day for context.)
- Stable energy. Lower glycemic load than white potato when boiled or steamed, which keeps post-meal energy steadier. Roasting and frying erase that advantage.
For a high-protein meal that uses sweet potato as the carb base, the sheet pan chicken and vegetables recipe is the simplest plate to build around it.
The honest takeaway
Sweet potato is a friendly food that becomes an unfriendly one through size creep, oil, and toppings. Weigh once, calibrate your eye, and the rest takes care of itself.
The actual rules:
- 130g raw, with skin, is one medium potato. That is 112 kcal.
- Baked is denser than boiled per 100g cooked. Use the right number for the method.
- Most "loaded" toppings double the calories. Butter, cheese, and sour cream add fast.
- Sweet potato fries are the same as regular fries, calorically. The "healthy" framing is marketing.
Track the potato, not the marketing.