How Many Calories in Seaweed? Nutrition Facts & Macros
A serving of dried nori (10 g, about 4 sheets) has 4 calories
Protein 0.6g · Carbs 0.5g · Fat 0g
Seaweed — specifically nori (laver) — is one of the most nutrient-dense foods per calorie on the planet: only 35 kcal per 100 g raw, yet packed with 5.81 g of protein, 146 mcg of folate (37% DV), and significant amounts of iodine — a mineral critical for thyroid function. Nori is the thin, dark-green seaweed sheet used to wrap sushi rolls. A single dried nori sheet weighs about 2.5 g and has only 7–8 kcal, making it virtually calorie-free as a snack. Here is everything you need to know about seaweed calories and macros, based on USDA data. Raw nori is approximately 85% water; dried nori is about 8% water.
146 kJ · per 100g · Water: 85.03 g
Calorie Calculator: Seaweed (Nori)
10 g Seaweed (Nori) contains 4 kcal
Calories by Portion Size
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| 1 dried nori sheet (2.5 g) | 1 kcal | 0.1g | 0.1g | 0g |
| 1 serving dried (10 g, ~4 sheets) | 4 kcal | 0.6g | 0.5g | 0g |
| 100 grams | 35 kcal | 5.8g | 5.1g | 0.3g |
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Seaweed (Nori) — Nutrition Facts
| Seaweed (Nori) | per 100g |
|---|---|
| Calories | 35 kcal |
| Protein | 5.81 g |
| Fat | 0.28 g |
| Carbs | 5.11 g |
| Fiber | 0.3 g |
| Sugar | 0.49 g |
| Sodium | 48 mg |
| Potassium | 356 mg |
| Magnesium | 2 mg |
| Phosphorus | 58 mg |
| Vitamin C | 39 mg |
| Vitamin B6 | 0.159 mg |
| Folate | 146 mcg |
| Manganese | 0.99 mg |
| Water | 85.03 g |
Source: USDA FoodData Central (FDC ID: 168458) · Data verified April 2026
Variations
Nori / Laver (default)
35 kcal per 100 g raw. The thin, dark-green seaweed sheet used for sushi rolls. Mild, slightly nutty flavour. One dried sheet (~2.5 g) has only 7–8 kcal. Rich in folate (146 mcg) and moderate in iodine. The most commonly consumed seaweed worldwide.
Wakame
45 kcal per 100 g raw. A soft, slightly sweet seaweed commonly used in miso soup and seaweed salad. Higher in calcium (150 mg per 100 g) than nori. Mild flavour, silky texture. Often sold dried — rehydrates in minutes. Very low in fat (0.64 g per 100 g).
Kelp / Kombu
43 kcal per 100 g raw. A thick, leathery seaweed used primarily for making dashi broth in Japanese cooking. Extremely high in iodine — one piece can exceed the daily recommended intake. Also a natural source of glutamate (umami). Not typically eaten in large quantities. Use with caution if you have thyroid issues.
Dulse
306 kcal per 100 g dried. A reddish-purple seaweed from the North Atlantic, popular in Irish, Icelandic, and Nordic cuisine. Smoky, slightly salty flavour — sometimes compared to bacon when pan-fried. Higher in protein (up to 20 g per 100 g dried) and iron than other seaweeds. Usually sold dried as flakes or whole leaves.
Dietary Perspectives
For Weight Loss
Seaweed is one of the best foods for weight loss — only 35 kcal per 100 g raw. Dried nori sheets are an almost calorie-free snack: one sheet (~2.5 g) has just 7–8 kcal. Despite the ultra-low calories, nori provides 5.81 g of protein per 100 g — more than most vegetables — which supports satiety. The rich mineral content (iodine, potassium, folate) helps maintain healthy thyroid function, which plays a key role in metabolism. Use nori sheets as a crispy low-calorie substitute for chips or crackers.
For Athletic Performance
Seaweed provides a unique micronutrient profile for athletes. The 5.81 g of protein per 100 g is notable for a vegetable, though small in absolute terms. The real value is in minerals: potassium (356 mg per 100 g) supports electrolyte balance during exercise, folate (146 mcg) is essential for red blood cell production, and iodine supports the thyroid-driven metabolic rate that fuels performance. Nori is practically calorie-free, so it does not contribute significantly to energy needs — use it as a nutrient-dense addition to rice bowls, wraps, or post-workout meals rather than a primary fuel source.
For Keto
Seaweed is one of the most keto-friendly foods available. Per 100 g raw, nori has only about 4.8 g net carbs (5.11 g total minus 0.3 g fiber). In practical portions — one dried sheet (~2.5 g) — the net carb count is negligible at under 0.2 g. It is essentially a free food on keto. The micronutrient density is the real benefit: iodine for thyroid support (critical when restricting carbs), potassium and magnesium for electrolyte balance, and folate. Use nori sheets as low-carb wraps for fish, avocado, or cream cheese — a perfect keto-friendly alternative to bread or tortillas.
Frequently Asked Questions
How many calories are in seaweed?
Raw seaweed (nori/laver) has only 35 calories per 100 g — one of the lowest-calorie foods available. A single dried nori sheet (~2.5 g) contains just 7–8 calories. A 10 g serving of dried nori (about 4 sheets) has approximately 35 calories. For comparison, spinach has 23 kcal and cucumber 15 kcal per 100 g.
Is seaweed rich in iodine?
Yes — seaweed is one of the richest natural sources of iodine. Nori contains roughly 30–45 mcg of iodine per sheet (varying by brand and origin), while kelp (kombu) can contain dramatically more — up to 2,000+ mcg per gram. The recommended daily intake of iodine is 150 mcg for adults. One or two nori sheets per day is safe and beneficial, but large amounts of kelp should be consumed with caution.
Is seaweed keto-friendly?
Seaweed is excellent for keto. Per 100 g raw, nori has 5.11 g total carbs minus 0.3 g fiber = about 4.8 g net carbs. Since you typically eat 2.5–10 g at a time (1–4 dried sheets), the actual net carb intake is negligible — under 0.5 g per sheet. It is virtually zero-calorie, zero-carb in practical portions, making it one of the most keto-friendly foods available.
Nori vs wakame vs kelp — what is the difference?
Nori (laver) is thin, dark-green, and used for sushi rolls — about 35 kcal per 100 g raw. Wakame is a softer, slightly sweet seaweed used in miso soup — about 45 kcal per 100 g. Kelp (kombu) is thick, leathery, and used to make dashi broth — about 43 kcal per 100 g. Kelp has extremely high iodine content. Dulse is a reddish seaweed from the Atlantic — about 306 kcal per 100 g dried. All are nutritious, but nori is the most commonly consumed worldwide.
Can I use seaweed for sushi at home?
Yes — nori sheets are specifically made for sushi. Buy roasted nori sheets (yaki-nori) at any Asian grocery or supermarket. Place the shiny side down on a bamboo mat, spread sushi rice, add fillings, and roll. Each nori sheet (~2.5 g) adds only 7–8 kcal to your roll. Store unused sheets in an airtight container to prevent moisture absorption — damp nori becomes chewy and loses its crispness.
Is it safe to eat seaweed every day?
Eating a few nori sheets daily is generally safe and nutritious. The main concern is iodine — especially from kelp (kombu), which can contain very high levels. Excessive iodine can disrupt thyroid function. Nori has moderate iodine levels and is safe for daily consumption. People with thyroid conditions should consult their doctor. Sodium content is low in raw nori (48 mg per 100 g), though flavored snack varieties may have more.
Compare with Similar Foods
| Portion | kcal | Protein | Carbs | Fat |
|---|---|---|---|---|
| Seaweed (Nori) | 35 | 5.81g | 5.11g | 0.28g |
| Spinach (Raw) | 23 | 2.86g | 3.63g | 0.39g |
| Broccoli | 34 | 2.82g | 6.64g | 0.37g |
| Cucumber | 15 | 0.65g | 3.63g | 0.11g |
| Tofu (Extra Firm) | 83 | 9.98g | 1.18g | 5.26g |
per 100g
Per 100 g, raw seaweed (nori) has only 35 kcal with 5.81 g of protein, 0.28 g of fat, and 5.11 g of carbs. It is an exceptional source of folate (146 mcg, 37% DV) and one of the richest natural sources of iodine — critical for thyroid health.
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