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Black tea is the familiar dark tea of breakfast blends and most tea bags: leaves of the tea plant that are fully processed until they turn dark, giving a brisk, malty cup. Brewed plain, it is almost calorie-free, and USDA FoodData Central lists a modest amount of caffeine and a useful share of the Daily Value for manganese per cup. Below are the USDA numbers for black tea nutrition and caffeine, how black tea vs green tea and coffee compare, what large studies say about black tea benefits, and the practical cautions: caffeine, iron absorption and oxalate.
Peptide Labs does not sell tea. This article is general nutrition information, not medical advice.
Key Takeaways
- Black, green and oolong teas all come from Camellia sinensis; black tea is fully fermented (oxidized).
- USDA lists brewed black tea with about 47 milligrams of caffeine and 2 calories per 8 fluid ounce cup.
- A cup also supplies about 23% of the Daily Value for manganese in USDA data.
- Large cohort studies link regular tea drinking with modestly lower death rates, but they cannot prove cause and effect.
- Tea polyphenols can reduce non-heme iron absorption from a meal; black tea also contains oxalate.
What is black tea?
According to NCCIH, the NIH center for complementary health, green, black and oolong teas all come from the same plant, Camellia sinensis, and differ in how the leaves are processed: green tea leaves are not fermented, oolong is partially fermented and black tea is fermented. In tea making, fermentation means enzymatic oxidation after the leaves are rolled or cut, not fermentation by microbes as in kombucha. A 2026 review in Food Chemistry describes how this step converts tea catechins into theaflavins, pigments that are characteristic of black tea and play an important role in its color and flavor.
Popular styles include Assam, Darjeeling, Ceylon and Keemun, and breakfast blends mix several of them. Earl Grey is black tea flavored with bergamot. Masala chai is black tea simmered with spices and milk, so its nutrition depends heavily on the milk and sugar added.
Black tea caffeine and nutrition (USDA)
Brewed tea is mostly water, so most nutrients are present only in small amounts. The table uses USDA SR Legacy values for an 8 fluid ounce cup (237 grams). USDA gives no serving size for oolong and uses a slightly larger cup for green tea, so those two rows are calculated at 237 grams for a fair comparison.
| Per 8 fl oz cup, brewed (USDA FDC ID) | Calories | Caffeine | Manganese (% DV) | Potassium (% DV) | Fluoride |
|---|---|---|---|---|---|
| Black tea (173227) | 2 | 47 mg | 0.52 mg (23%) | 88 mg (2%) | 884 mcg |
| Black tea, decaffeinated (174871) | 2 | 2 mg | 0.52 mg (23%) | 88 mg (2%) | Not listed |
| Oolong tea, calculated (174120) | 2 | 38 mg | 0.50 mg (22%) | 28 mg (1%) | Not listed |
| Green tea, calculated (171917) | 2 | 28 mg | 0.44 mg (19%) | 19 mg (less than 1%) | Not listed |
| Brewed coffee (171890) | 2 | 95 mg | 0.05 mg (2%) | 116 mg (2%) | 215 mcg |
In USDA data, a cup of brewed black tea has about half the caffeine of a cup of brewed coffee and more than the same cup of green or oolong tea. The FDA’s own consumer table, which uses 12 fluid ounce drinks, puts typical black tea at about 71 milligrams and green tea at about 37 milligrams, while regular brewed coffee ranges from 113 to 247 milligrams. Real cups vary with the leaf, the brand and how strong you brew, so read any single number as an estimate.
For context, the FDA has cited 400 milligrams of caffeine a day as an amount not generally associated with negative effects for most adults, while stressing that sensitivity varies widely and that this figure covers caffeine from all sources. Our guide to caffeine limits explains that FDA statement, and our caffeine pills guide covers concentrated caffeine. Decaf black tea is low in caffeine but, as the FDA puts it, decaffeinated does not mean caffeine-free.
The manganese figure is the one nutrient that stands out: USDA data put a cup of black tea at close to a quarter of the Daily Value, which is why tea appears in our list of manganese sources. USDA also lists fluoride for brewed black tea; there is no FDA Daily Value for fluoride. For a plain coffee comparison, see our guide to black coffee calories.
How black tea compares with other teas
The black tea vs green tea question mostly comes down to processing. Both start as the same leaves. Green tea is heated soon after picking to stop oxidation, so it keeps more of its original catechins and tastes grassy or vegetal; black tea is allowed to oxidize fully, which builds theaflavins and a darker, stronger flavor. In USDA data, black tea also carries more caffeine per cup. Our green tea guide covers that tea’s research, and our matcha guide covers the powdered form, where you drink the whole leaf.
- Black tea: fully fermented, dark, malty or brisk; the most caffeine of these three in USDA data.
- Oolong tea: partially fermented, sitting between green and black in color, flavor and USDA caffeine.
- Green tea: not fermented; the least caffeine of the three per brewed cup in USDA data.
- Herbal teas: not from Camellia sinensis at all, such as chamomile, hibiscus or ginger, and usually caffeine-free unless blended with tea.
Black tea benefits: what the research shows
Most human evidence on tea comes from observational studies, which follow large groups of people and look for patterns. They can show associations but cannot prove that tea caused an outcome, because tea drinkers may differ from non-drinkers in many other ways.
- UK Biobank (2022, Annals of Internal Medicine): researchers followed 498,043 adults aged 40 to 69 for a median of 11.2 years, in a population where black tea is the main type drunk. People who drank more tea had a modestly lower death rate from any cause than non-drinkers. Intake was self-reported, and the authors note that portion size and tea strength were not assessed.
- Beverages and kidney stones (2013, Clinical Journal of the American Society of Nephrology): across three US cohorts with 194,095 participants, people in the highest tea-drinking category had an 11% lower rate of new kidney stones than those in the lowest, while sugar-sweetened cola was linked with a higher rate. This is an association; whether tea suits someone who forms stones is a question for their clinician.
- Lab chemistry: theaflavins and other tea polyphenols are studied in the lab, but lab activity does not show an effect in people who drink tea.
Black tea and iron absorption
The NIH Office of Dietary Supplements explains that certain polyphenols in plant foods reduce the absorption of non-heme iron, the form found in plant foods and fortified grains, while vitamin C and meat improve it. Its fact sheet does not single out tea, but a classic 1999 study in the British Journal of Nutrition did: in adults eating a bread meal, black tea cut non-heme iron absorption by 79% to 94% compared with water, and adding milk made little or no difference. Herb teas, coffee and cocoa also reduced absorption in that study.
This matters most for people at risk of low iron; the ODS fact sheet lists groups such as people with heavy menstrual bleeding and frequent blood donors. If that is you, ask your clinician or a dietitian whether drinking tea between meals rather than with them makes sense for you. Our guide to foods high in iron explains heme and non-heme iron.
Oxalate and kidney stones
Black tea contains oxalate, a compound studied in kidney stone research. A 2013 lab study in Urolithiasis measured 25 loose black teas and 10 tea-bag brands and found soluble oxalate rose steadily with longer brewing. In a small 2007 Polish study of 22 people with oxalate stones, regular tea and coffee supplied most of the oxalate in their diets. Set against that, the large 2013 cohort above linked tea with fewer new stones overall. If you have had a kidney stone, follow the plan from your own clinician; our oxalates guide explains the background.
Sweet tea, bottled tea and milk
Much of the black tea Americans drink is sweetened. USDA SR Legacy lists a sweetened ready-to-drink lemon black tea (FDC 171888) at 122 calories and 25.7 grams of total sugars per 271 gram cup, compared with 2 calories for plain brewed tea. Unsweetened bottled black tea (FDC 174144) is listed at about 52 milligrams of caffeine per 16 fluid ounce bottle in USDA data. Check the Nutrition Facts label for added sugars, and see our milk guide if you add dairy.
Who should be careful with caffeinated tea
- Pregnancy and breastfeeding: the FDA advises talking to your health care provider about whether you need to limit caffeine if you are pregnant, trying to become pregnant or breastfeeding.
- Medicines and conditions: the FDA notes that some conditions and some medications make people more sensitive to caffeine. Ask a pharmacist if you are unsure.
- Children and teens: the FDA suggests talking with your health care professional about a child’s or teen’s caffeine.
- Signs of too much caffeine: the FDA lists a fast heart rate, palpitations, trouble sleeping, anxiety, jitters, upset stomach, nausea and headache. Talk to a clinician if these happen.
- Allergy: tea is not one of the nine major food allergens under US law, but any food can cause a reaction; see an allergist for unclear symptoms.
Frequently Asked Questions
How much caffeine is in black tea?
USDA lists about 47 milligrams in an 8 fluid ounce cup of brewed black tea; the FDA puts a typical 12 fluid ounce black tea at about 71 milligrams. Strength and brand change the real amount.
Does black tea have more caffeine than coffee?
No. In USDA data a cup of brewed coffee has about twice the caffeine of a cup of brewed black tea.
Is black tea vs green tea a big difference nutritionally?
Both are nearly calorie-free with small mineral amounts. Black tea is fully oxidized, has more caffeine per cup in USDA data and contains theaflavins; green tea keeps more catechins.
Does black tea affect iron absorption?
It can. A 1999 study found black tea sharply reduced non-heme iron absorption from a meal. People with low iron should ask a clinician how tea fits their diet.
Is decaf black tea caffeine-free?
No. USDA lists about 2 milligrams per cup, and the FDA notes that decaffeinated does not mean caffeine-free.
What are the main black tea benefits?
Plain black tea is a nearly calorie-free drink that supplies manganese. Large cohort studies link tea drinking with modestly lower death rates, but they cannot prove cause and effect.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Oolong Tea: Benefits, Caffeine, Nutrition and Research, Green Tea Benefits: What the Research Shows, Caffeine and Side Effects, How Much Caffeine Is Too Much? Daily Limits, Overdose Signs and Label Math.