How Many Carbs in a Sweet Potato?
How many carbs in a sweet potato? One medium baked tuber (114 g, skin on) is about 24 g carbohydrate, 4 g fiber, and ~20 g net carbs on USDA FoodData Central rows — roughly 103 kcal with 2 g protein. A large baked potato (180 g) is about 37 g carbohydrate. Size moves the number more than the color on the skin.
Carbs in a medium sweet potato by size (USDA)
Sweet potato carbohydrate scales with cooked edible weight. You do not need a tuber-specific formula; you need a portion habit so the next ten dinners are not a guess. USDA baked-in-skin rows are the cleanest default when you ate the potato whole from the oven.
| Size (USDA habit) | Cooked weight | kcal | Total carb | Fiber | Net carb (carb − fiber) |
|---|---|---|---|---|---|
| Per 100 g, baked in skin | 100 g | ~90 | ~21 g | ~3.3 g | ~18 g |
| Small | ~90 g | ~81 | ~19 g | ~3 g | ~16 g |
| Medium | ~114 g | ~103 | ~24 g | ~4 g | ~20 g |
| Large (long store tuber) | ~180 g | ~162 | ~37 g | ~6 g | ~31 g |
| 1 cup mashed, plain | ~200 g | ~180 | ~41 g | ~7 g | ~34 g |
Carbs in a medium sweet potato — the query most people type — map to the ~114 g row: ~24 g total, ~20 g net. If your grocery sells a longer 5-inch potato (~130 g), scale up to about 27 g carbohydrate using the per-100 g column.
Put the cooked potato on a kitchen scale once. Reuse that gram number while the bag from your store stays the same size.
If you track net carbs the Atkins way, one medium sweet potato is about 20 g net. That can be an entire 20 g daily cap. It still fits a moderate carb day from the carbohydrate calculator; it does not fit a strict keto morning unless the rest of the day stays nearly starch-free.
Key takeaway: Medium means ~114 g and ~24 g carbohydrate on USDA rows — not whatever tuber was in the bin. Name the size or weigh the cooked portion.
Net carbs, keto caps, and what "clean carb" does not mean
Total carbohydrate minus fiber is how most low-carb trackers define net carbs for whole foods. A plain baked sweet potato has no sugar alcohols. Do not subtract fiber twice.
| Nutrient (medium, ~114 g baked) | Amount |
|---|---|
| Calories | ~103 kcal |
| Total carbohydrate | ~24 g |
| Fiber | ~4 g |
| Net carbohydrate | ~20 g |
| Protein | ~2 g |
| Fat | ~0.2 g |
Fitness culture calls sweet potatoes a "clean" starch. Clean is not a gram count. The tuber is still most of a small carb budget if you are doing keto or Atkins-style net carbs.
If you use the keto macro calculator with a 30 g cap, a whole medium potato is most of the day. A 20 g cap cannot absorb a 20 g net side and still leave room for sauce, milk, and vegetables.
A few bites of sweet potato on a mixed plate — 40–60 g cooked — might be 8–12 g carbohydrate. That is a different decision from logging "I had a sweet potato" when you ate the whole tuber plus cinnamon sugar.
Key takeaway: "Clean" does not lower grams. Keto-sized caps and a whole medium sweet potato rarely share a day unless the rest of the plate is nearly carb-free.
Sweet potato versus white potato and other starches
People swap sweet potato for white potato expecting fewer carbs. Both are starches. Color changes micronutrients, not the fact that you are eating a tuber.
| Food | Typical portion | Approx. total carb | Approx. fiber | Notes |
|---|---|---|---|---|
| Sweet potato, baked | Medium ~114 g | ~24 g | ~4 g | Skin on, USDA row |
| White potato, baked | Medium ~173 g | ~37 g | ~4 g | Larger default USDA medium |
| Medium banana | ~118 g | ~27 g | ~3 g | See banana calories |
| Cooked white rice | 1 cup ~158 g | ~45 g | ~1 g | See rice calories |
Per 100 g, sweet potato baked in skin runs about 21 g carbohydrate. Some white potato rows land near 17–20 g per 100 g depending on variety and cooking method — so "sweet potato has fewer carbs" is not automatically true by weight. What sweet potato often adds is fiber and vitamin A, not a carb exemption.
White potatoes are also starch. Switching colors does not create a low-carb food. Fries, marshmallow toppings, and brown sugar change the row. Butter is extra fat, not fewer carbs.
Choosing sweet potato versus rice as your dinner starch? Compare the grams you actually plate, not a textbook 100 g line you never eat.
Key takeaway: Sweet potato and white potato both spend a carb budget. Weigh the portion; do not trust the orange color to do the math.
How trackers get sweet potato carbs wrong
Cronometer, MacroFactor, and MyFitnessPal all accept 114 g or 180 g if you type it. The miss is rarely chemistry. It is portion theater — the default "1 sweet potato" row does not know what was on your baking sheet.
| What got logged | What was eaten | Drift |
|---|---|---|
| "1 sweet potato" medium (~24 g carb) | Large ~180 g baked | 24 g → ~37 g carb |
| "Low carb dinner" with whole medium | Same potato + 20 g keto cap | 20 g net used the entire cap |
| Baked potato row | 150 g fries + pan oil | Starch plus 119+ kcal of fat |
Worked example: You bake one large sweet potato (~180 g) and log medium (~24 g carbohydrate). You under-count by ~13 g carbohydrate once. Do that four dinners a week and you are ~52 g carbohydrate off the log without changing a recipe — enough to explain a stalled cut or a keto test strip that never turns.
Weigh the cooked potato you eat, once. Save the grams as a custom food in MacroFactor or a note in Cronometer. Reuse until the bag from your store changes.
Apple Health and Garmin only display the total the tracker already accepted. Fix the gram row upstream.
Key takeaway: Trackers only know the row you tapped. Match grams or USDA size to the tuber you actually ate.
Baked, mashed, fries, and the toppings
Plain baked or boiled follows the table above. Mashed with milk and butter is a recipe: potato plus dairy plus fat. A restaurant mash can hide more butter than a home teaspoon.
Fries are starch plus frying oil. The carb grams follow the potato weight. The calories climb with oil. Do not copy the baked 90 kcal/100 g row onto a fried basket.
| Preparation | What changes | Carb note |
|---|---|---|
| Baked in skin | Water loss, concentrated starch per 100 g | Use baked row |
| Boiled, no skin | Slightly more water in flesh | Slightly lower carb per 100 g — pick boiled row |
| Pan fries | Oil + often larger eaten weight | Starch from potato weight; fat is separate |
| Loaded with sugar and marshmallows | Added sugar on starch | Log toppings as their own foods |
Cinnamon is free enough to ignore. Brown sugar is not. Mini marshmallows are not. A "loaded" sweet potato with butter, sugar, and pecans is a dessert that started in the ground.
If the potato is a training carb next to chicken, it can do useful work. If it is the vehicle for a sugar crust, log the crust.
Key takeaway: Cooking method and toppings decide calories. The starch grams still come from the tuber's weight — oil does not subtract carbohydrate.
When a sweet potato fits your day — and when it does not
On a moderate carb target from the carbohydrate calculator, one medium sweet potato is a reasonable starch with potassium and vitamin A. The Dietary Guidelines treat starchy vegetables as their own subgroup — not as free volume.
Common patterns:
- Post-workout dinner. Medium sweet potato ~24 g carbohydrate beside chicken or fish. Starch refills glycogen; protein still comes from the plate.
- Meal-prep bowls. Half a medium potato (~12 g carbohydrate) plus rice on the same day stacks fast — log both.
- Keto test. Whole medium at ~20 g net leaves almost nothing for vegetables, sauce, or dairy. A few bites might fit; the whole tuber usually does not.
- "Healthy" holiday side. The potato plus marshmallows is two carb sources, not one virtuous tuber.
Run the subtraction in the net carb calculator on the weight you actually ate — then look at the rest of the day before you add a second starch.
This guide is educational food math, not medical advice. If you follow a prescribed carb cap from a clinician, use the gram table with whoever set the plan.
Key takeaway: A medium sweet potato is a starch serving, not a free vegetable. It fits moderate carb days; it fights strict keto caps.
A simple logging method
- Weigh the cooked sweet potato, or pick small / medium / large from the table on purpose.
- In MyFitnessPal, Cronometer, or MacroFactor, enter grams or the USDA size that matches.
- If you count net carbs, subtract fiber once — or use the net carb calculator.
- Add butter, oil, brown sugar, and marshmallows as their own foods.
You do not need to drop sweet potatoes to eat well. You need the tuber to match the cap you claimed you were using.
When the question is "how many net carbs is this potato," weigh first, subtract fiber once, then decide whether this side is the day's starch before you reach for rice or bread.
Key takeaway: Weigh the cooked potato, subtract fiber once if you count net carbs, and treat toppings as their own foods. The orange color does not spend the grams for you.