Carbs in Tomatoes: Per Tomato, Per Cup, and By Type
Tomatoes are low in carbohydrates. Most of their carb content comes from simple sugars — mainly fructose and glucose — with a small contribution from fiber. Whether you are managing carb intake, following a low-carb diet, or simply want to understand what is in a tomato, this page gives you exact numbers across every common serving size, variety, and preparation method.
Quick Answer: How Many Carbs Are in a Tomato?
A medium raw tomato (about 123g) contains approximately 4.8 grams of total carbohydrates. Per 100g, raw tomatoes provide around 3.9g of total carbs. Net carbs — total carbs minus fiber — come to approximately 3.3g per 100g.
- Per 100g (raw): ~3.9g total carbs | ~3.3g net carbs
- Medium tomato (123g): ~4.8g total carbs | ~4.1g net carbs
- One cup chopped (180g): ~7.0g total carbs | ~5.8g net carbs
- Cherry tomato (17g): ~0.7g total carbs | ~0.6g net carbs
- Large beefsteak tomato (182g): ~7.1g total carbs | ~5.9g net carbs
What Carbs Are Actually in a Tomato?
The carbohydrates in a raw tomato break down into three components: sugars, fiber, and a very small amount of starch.
Sugars
The majority of tomato carbs are simple sugars — roughly equal parts fructose and glucose. These are the natural sugars that give ripe tomatoes their sweet, slightly tangy flavor. Per 100g of raw tomato, total sugars are approximately 2.6g.
Fiber
Raw tomatoes contain modest dietary fiber — around 1.2g per 100g. The fiber is found mainly in the skin and seed cavity. See the related fiber in tomatoes guide for a full breakdown.
Starch
The starch content of a ripe raw tomato is negligible — typically under 0.1g per 100g. Green (unripe) tomatoes contain slightly more starch, which converts to sugar as the tomato ripens.
Carbs in Tomatoes by Serving Size
| Serving | Weight | Total Carbs | Fiber | Net Carbs | Sugars |
|---|---|---|---|---|---|
| 1 cherry tomato | 17g | 0.7g | 0.2g | 0.5g | 0.4g |
| 1 plum / Roma tomato | 62g | 2.4g | 0.7g | 1.7g | 1.6g |
| 1 medium round tomato | 123g | 4.8g | 1.5g | 3.3g | 3.2g |
| 1 large beefsteak tomato | 182g | 7.1g | 2.2g | 4.9g | 4.7g |
| 1 cup chopped raw tomato | 180g | 7.0g | 2.2g | 4.8g | 4.7g |
| 1 cup cherry tomatoes | 149g | 5.8g | 1.8g | 4.0g | 4.0g |
| 100g raw tomato | 100g | 3.9g | 1.2g | 2.7g | 2.6g |
All values are for raw, whole tomatoes with no added ingredients. Source: USDA FoodData Central.
Carbs in Tomatoes by Variety
Most common tomato varieties fall within a narrow carbohydrate range of 3.5–5g per 100g. The differences are small, but varieties with denser flesh, less water, or higher sweetness tend to sit at the higher end.
| Tomato Type | Total Carbs per 100g | Net Carbs per 100g | Notes |
|---|---|---|---|
| Standard round / slicing | ~3.9g | ~2.7g | Most common reference variety |
| Cherry tomato | ~4.0g | ~2.9g | Slightly sweeter per gram |
| Grape tomato | ~4.5g | ~3.5g | Denser, higher sugar concentration |
| Roma / plum tomato | ~3.8g | ~2.7g | Less water, meaty flesh |
| Beefsteak tomato | ~3.9g | ~2.7g | High water content, large size |
| Heirloom tomato | ~3.9–4.8g | ~2.8–3.6g | Varies by cultivar |
| Green (unripe) tomato | ~5.1g | ~3.9g | More starch, less sugar than ripe |
How Processing and Cooking Change Carb Content
Cooking a tomato does not add or remove carbohydrates from the food itself — but it does remove water. When water leaves a tomato through cooking, the remaining nutrients become more concentrated per gram and per cup. This means cooked tomato products can appear much higher in carbs than raw tomatoes, even though no carbs were added.
Carbs in Processed Tomato Products
| Tomato Product | Total Carbs per 100g | Net Carbs per 100g | Notes |
|---|---|---|---|
| Raw tomato | ~3.9g | ~2.7g | Baseline |
| Canned whole tomatoes (no salt) | ~3.5g | ~2.5g | Similar to raw; water retained in can |
| Tomato sauce (plain, canned) | ~7.1g | ~5.7g | Reduced, more concentrated |
| Crushed tomatoes (canned) | ~5.0g | ~3.9g | Moderate concentration |
| Tomato paste | ~18.9g | ~14.5g | Highly concentrated — used in small amounts |
| Tomato juice (unsalted) | ~4.2g | ~3.8g | Low fiber after juicing |
| Sun-dried tomatoes (dry pack) | ~55.8g | ~43.6g | Extreme concentration; used in small amounts |
| Stewed tomatoes (no added sugar) | ~7.0g | ~5.8g | Slightly higher than raw per 100g |
Tomato paste and sun-dried tomatoes are the most important products to track. Although they appear high in carbs per 100g, typical serving sizes are small — a tablespoon of tomato paste weighs about 16g and contains roughly 3g of carbs.
Tomato Carbs and Low-Carb Diets
Tomatoes are considered low-carb by most dietary standards. A medium raw tomato provides fewer than 5g of total carbs and under 4g of net carbs. For reference, most low-carb diet frameworks set a daily carb limit anywhere from 20g to 100g depending on the approach.
Are Tomatoes Keto-Friendly?
Fresh raw tomatoes are generally considered compatible with ketogenic diets when eaten in moderate portions. A medium tomato contributes around 3–4g of net carbs toward a daily limit of 20–50g. Cherry tomatoes, often eaten in larger volumes, can add up more quickly — about 4g of net carbs per cup.
Tomato-based products like tomato paste, tomato sauce, and ketchup require more attention on a strict keto diet because of their concentrated carb content or added sugars.
Tomatoes vs Other Common Vegetables
Compared to other vegetables commonly eaten raw or in salads, tomatoes are among the lower-carb options:
- Tomato (raw, 100g): ~3.9g total carbs
- Cucumber (raw, 100g): ~3.6g total carbs
- Bell pepper (raw, 100g): ~6.0g total carbs
- Carrot (raw, 100g): ~9.6g total carbs
- Onion (raw, 100g): ~9.3g total carbs
- Zucchini (raw, 100g): ~3.1g total carbs
Tomatoes sit comfortably alongside cucumber and zucchini as one of the lower-carb salad and cooking vegetables.
Net Carbs in Tomatoes
Net carbs are calculated by subtracting dietary fiber from total carbohydrates. Fiber is a carbohydrate that the human body cannot fully digest, so it does not raise blood glucose in the same way that digestible carbs do. For this reason, many people tracking carbs — particularly on low-carb or keto diets — use net carbs rather than total carbs.
For raw tomatoes, subtracting the ~1.2g of fiber per 100g from the ~3.9g total carbs gives a net carb value of approximately 2.7g per 100g. For a full breakdown of fiber values specifically, see the net carbs in tomatoes guide and the fiber in tomatoes guide.
Frequently Asked Questions
How many carbs are in a tomato?
A medium raw tomato (about 123g) contains approximately 4.8g of total carbohydrates and around 3.3g of net carbs after subtracting fiber.
How many carbs are in 100g of tomato?
Raw tomatoes contain approximately 3.9g of total carbohydrates per 100g. Net carbs are around 2.7g per 100g after subtracting roughly 1.2g of dietary fiber.
Are tomatoes high in carbs?
No. Tomatoes are low in carbohydrates. Most of their weight is water. A full cup of chopped raw tomatoes contains only about 7g of total carbs, making them one of the lower-carb vegetables available.
How many carbs are in cherry tomatoes?
One cup of cherry tomatoes (about 149g) contains approximately 5.8g of total carbs and around 4.0g of net carbs. A single cherry tomato contains roughly 0.7g of total carbs.
How many carbs are in Roma or plum tomatoes?
A single Roma tomato (about 62g) contains approximately 2.4g of total carbs and around 1.7g of net carbs. Roma tomatoes are slightly denser than round tomatoes but are in the same low-carb range per 100g.
How many carbs are in tomato paste?
Tomato paste contains approximately 18.9g of total carbs per 100g. However, typical servings are small — a tablespoon of tomato paste (about 16g) contains roughly 3g of carbs. The high per-100g figure reflects the extreme concentration of reduced tomatoes.
Do tomatoes have more carbs when cooked?
Per gram, yes. Cooking removes water, which concentrates carbohydrates into a smaller volume. The carbs in the tomato itself have not changed — there are simply fewer grams of food per cup because water has evaporated.
Are tomatoes suitable for a keto diet?
Fresh tomatoes are generally considered compatible with ketogenic diets in moderate portions. A medium tomato contributes around 3–4g of net carbs. Heavily processed tomato products like paste or ketchup require closer attention due to their concentrated carb content.
What is the difference between total carbs and net carbs in tomatoes?
Total carbs in a raw tomato include all carbohydrates — sugars, fiber, and trace starch. Net carbs subtract dietary fiber, which is not fully digested. Per 100g of raw tomato, total carbs are approximately 3.9g and net carbs are approximately 2.7g.
Related Tomato Nutrition Guides
- Tomato Nutrition Facts – Complete Guide
- Calories in Tomatoes: Per Tomato, Per Cup, and By Type
- Net Carbs in Tomatoes
- Fiber in Tomatoes
- Sugar in Tomatoes
- Lycopene in Tomatoes
- Potassium in Tomatoes
- Canned Tomatoes Nutrition
Summary
Raw tomatoes are low in carbohydrates. A medium tomato contains under 5g of total carbs and under 4g of net carbs. Carb content stays low across all fresh varieties, with only small differences between types. Cooked and concentrated tomato products contain more carbs per gram due to water loss — tomato paste being the most significant example.
For most dietary approaches, including low-carb and keto, fresh tomatoes are a practical, low-carb ingredient. For the full nutrition picture, see the tomato nutrition facts pillar page.