How much sugar is in sweet potato?
Sweet potato has 8.5 g of sugar per 1 medium (130 g) — about 2 teaspoons. That's 6.5 g per 100 g, and it's all naturally occurring — whole sweet potato has no added sugar.
USDA FoodData Central · baked in skin, flesh · FDC 168483
Sugar by portion
| Portion | Sugar | ≈ teaspoons | Total carbs | Calories |
|---|---|---|---|---|
| 1 medium (130 g) | 8.5 g | 2 tsp | 26.9 g | 117 |
| 100 g | 6.5 g | 1.5 tsp | 20.7 g | 90 |
| 1 oz (28 g) | 1.8 g | 0.4 tsp | 5.9 g | 26 |
Teaspoon figure converts grams of sugar at ~4.2 g per level teaspoon, for scale only. This is the total sugar naturally present — whole sweet potato carries no added sugar. Values from USDA per-100 g data (FDC 168483, SR Legacy). baked in skin, flesh.
A medium baked sweet potato carries about 8.5 g of sugar — roughly 2 teaspoons — which comes from 6.5 g per 100 g, and it’s entirely naturally occurring, with no added sugar in a plain sweet potato. That’s a moderate amount for a starchy vegetable: noticeably more than a white potato, less than most fruit. It also isn’t free sugar sitting on top — it’s woven into a whole-food package of fiber and slow-digesting starch, which is what makes the sweet potato a genuinely nutritious carb rather than a sweet treat, even though it tastes like one.
Natural sugar, but baking concentrates it
Here’s the part the sweetness hides. The 6.5 g per 100 g is the figure for the baked vegetable, and baking is exactly why a sweet potato tastes so sugary. As it cooks, an enzyme converts some of the potato’s starch into sugar, and the dry heat of an oven drives off water while caramelizing those sugars on the surface — so a baked or roasted sweet potato reads far sweeter on the tongue than a boiled one, where less of that happens and more water stays in. The natural sugar starts modest; the cooking method is what brings the sweetness forward. None of that adds sugar from outside the potato — it’s the vegetable’s own carbohydrate transformed by heat. The honest summary is that a sweet potato is a whole-food sugar-and-starch package with fiber attached, and roasting simply makes its built-in sweetness more obvious.
Where the sugar actually piles up
The number to worry about isn’t the potato — it’s what gets done to it. A plain baked sweet potato stays near 8.5 g of natural sugar; candied yams, marshmallow-topped casseroles, and brown-sugar or maple glazes pour on added sugar that can dwarf the vegetable’s own, turning a nutritious side into something closer to dessert. Those are different foods entirely. Compared with a regular potato — which has well under 1 g of sugar per 100 g — the sweet potato is the sweeter of the two by a wide margin, but it pays you back with more fiber and a full day’s worth of vitamin A from its beta-carotene. So eat the sweet potato for what it is: a wholesome, naturally sweet carbohydrate. Just keep the glazes and marshmallows in view, since that’s where the real sugar load hides. This is general guidance, not medical advice.
For the rest of the nutrition picture — and why “healthy” doesn’t mean “high-protein” here — see protein in sweet potato.
Frequently Asked Questions
How much sugar is in a sweet potato?
About 8.5 g of sugar in one medium baked sweet potato (130 g), which is 6.5 g per 100 g (USDA FDC 168483). That's roughly 2 teaspoons, and it's all naturally occurring — there's no added sugar in a plain sweet potato.
How many teaspoons of sugar is that?
About 2 teaspoons per medium sweet potato, using 4.2 g of sugar per level teaspoon. For a starchy vegetable that's a moderate amount — more than a regular potato, less than most fruit — and it comes packaged with fiber and a slow-digesting starch, not as free sugar.
Is the sugar in sweet potato natural or added?
Entirely natural. A plain baked sweet potato contains only the vegetable's own sugars and nothing added (USDA FDC 168483). The picture changes fast with candied yams, marshmallow-topped casseroles, and brown-sugar or maple glazes — those add several times more sugar than the potato itself carries.
Why does a baked sweet potato taste so sweet?
Baking concentrates and develops the sugar. As a sweet potato cooks, an enzyme converts some of its starch into sugar, and the dry heat drives off water while caramelizing those sugars — so a baked sweet potato tastes much sweeter than a boiled one, even though the natural sugar started around 6.5 g per 100 g. Boiling tends to leave it less sweet; roasting and baking bring the sweetness forward.
Is sweet potato OK on a low-sugar or diabetic diet?
It's more about total carbohydrate than sugar. The ~8.5 g of natural sugar is moderate, but a medium sweet potato is roughly 27 g of total carbs, so it lands as a real carbohydrate serving even though the sugar is modest. The fiber and slow starch soften the blood-sugar rise, and pairing it with protein and fat helps further; on strict keto it's usually limited. This is general information, not medical advice.
When was this data last verified?
2026-06-18, against USDA FoodData Central FDC 168483 (Sweet potato, cooked, baked in skin, flesh, without salt; SR Legacy). We re-verify reference pages periodically and update when USDA revises the entry.
Whole-food values are USDA reference data, not a Labelgrade (that score is for branded packaged products, where we penalize added sugar). See our methodology and the added-sugar calculator.