Siyah Çay Kafeini: Bilmeniz Gereken Her Şey

A 240 ml cup of black tea has 47 mg of caffeine.

• A standard 240 ml cup of black tea contains 47 mg of caffeine.
• Black tea typically has about 47 mg vs. green tea 28 mg and white tea 16 mg per 240 ml.
• Compared with drip coffee (240 ml, 96 mg), black tea has roughly 49% of the caffeine per cup.
• After ~6 hours about 48% of a dose remains—so from 47 mg, ~22.6 mg is left.

Caffeine content in black tea: the baseline

Across published nutrient data a 240 ml (8 fl oz) serving of brewed black tea is listed at 47 mg of caffeine (≈19.6 mg/100 ml). Those are average values collected by major datasets and commonly cited by USDA FoodData Central. That single number is a good starting point when you plan intake or compare beverages.

How black tea compares: table of common drinks

Use this quick table to compare common teas, coffees and energy drinks by the dataset values.

Why black tea numbers vary: leaf, steeping and serving size

Leaf type and processing

Black tea is fully oxidized; oxidation concentrates certain alkaloids and produces a higher average caffeine than green or white tea. Within black tea, cultivars and plucking standard matter: a fine bud-and-leaf harvest (breakfast blends) tends to yield more caffeine per cup than coarse broken-leaf blends.

Steeping time, water temperature, and tea-to-water ratio

Longer steep time and hotter water extract more caffeine. A 1–2 minute bag steep yields less caffeine than a 4–5 minute steep; a stronger leaf-to-water ratio scales caffeine up roughly linearly. Bag tea often yields values close to the dataset averages; loose-leaf strong brews can exceed them.

Serving size

Dataset values use 240 ml. If you sip a 360 ml mug, multiply mg per 240 ml by 1.5 to estimate total caffeine.

Black tea vs coffee and energy drinks: practical comparisons

Black tea (47 mg per 240 ml) sits between low-caffeine green/white tea and brewed coffee. Drip coffee at 240 ml contains 96 mg—so a cup of black tea delivers roughly half the caffeine of an equivalent cup of drip coffee. Espresso shots are concentrated: a single 30 ml shot contains 63 mg.

How long caffeine from black tea stays in your body (decay math)

Population-average half-life is about 5.7 hours; caffeine declines roughly by half every 5.7 hours. Practically that means after 3 hours ≈69% remains, after 6 hours ≈48%, after 9 hours ≈33%, after 12 hours ≈23% remains.

Those are population averages. Genetics, liver function, pregnancy, some medications and smoking change the half-life. For example, pregnancy prolongs clearance (Mayo Clinic notes altered metabolism), while smoking speeds it up.

Health, safety and timing

Regulatory guidance: the U.S. Food and Drug Administration recommends up to 400 mg/day of caffeine for healthy adults; for pregnant individuals many authorities (including EFSA and clinical guidance) advise keeping intake near or below 200 mg/day. The American Academy of Pediatrics discourages routine caffeine use in adolescents. These limits help reduce risks of insomnia, palpitations and anxiety.

Timing: because meaningful caffeine remains even 6–12 hours after a cup, avoid late-afternoon cups if you want minimal sleep disruption. If you need precise tracking of intake and timing, use an app like CoffeeLog to log drink type, serving and when you consumed it.

Practical tips to lower or raise caffeine from black tea

• Reduce steep time: cut from 4–5 minutes to 1–2 minutes to lower extraction.
• Use fewer tea leaves or a larger cup to dilute mg per serving.
• Choose white or green tea (16 mg or 28 mg per 240 ml) for lower caffeine.
• Try decaffeinated black tea (not in dataset—typically >90% reduction) if you need near-zero caffeine.

Measuring and tracking your intake

For day-to-day decisions convert drinks to mg and add them: two 240 ml cups of black tea (2 × 47 mg = 94 mg) plus a 240 ml drip coffee (96 mg) totals 190 mg. Tracking tools and apps like CoffeeLog make this arithmetic automatic and show timing, which is helpful since residual mg matter for sleep and sensitivity.

Sources and further reading: caffeine content values are drawn from standardized food composition datasets (USDA FoodData Central and industry published product data). For health guidance see the U.S. Food and Drug Administration, European Food Safety Authority, Mayo Clinic and American Academy of Pediatrics. This page is informational, not medical advice—consult a clinician for personalized recommendations.

How many 240 ml cups of black tea will hit the 400 mg daily limit or the 200 mg pregnancy limit?

Nine 240 ml cups of black tea exceed the U.S. Food and Drug Administration's 400 mg/day recommendation: 9 × 47 mg = 423 mg, while 8 × 47 mg = 376 mg stays below the FDA limit (the FDA puts the 400 mg/day guidance at this level).

A pregnant individual should keep total daily caffeine near or below 200 mg/day, so five 240 ml cups of black tea would exceed that threshold: 5 × 47 mg = 235 mg, while 4 × 47 mg = 188 mg remains under the limit (the European Food Safety Authority and the NHS advise ~200 mg/day in pregnancy).

"A standard cup" is 240 ml.

Use the site's safe daily limit tool to translate a body-weight limit into mg and compare it to multiples of a 240 ml black tea serving, and see how a mixed set of drinks stacks up on our caffeine comparison page.

If I drink a 240 ml cup of black tea at 6:00 PM, how much caffeine will be in my body at 11:00 PM?

Using this page's decay model (population-average half-life 5.7 hours), a 240 ml cup at 6:00 PM leaves about 25.6 mg of caffeine at 11:00 PM: 47 mg × 0.5^(5/5.7) ≈ 47 × 0.5446 ≈ 25.6 mg.

That amount is meaningful because a large trial found that doses of 400 mg taken 6 hours before bedtime reduced total sleep time by more than an hour (Drake et al., 2013), so even smaller residual amounts like 25 mg can matter for sensitive sleepers (the Drake et al. study documents sleep impact from evening caffeine).

"Half-life" is the time it takes for the body to eliminate half of a substance's amount.

If you want an automated answer for your specific bedtime, try the latest-cup-before-bed tool to enter time and serving and get a tailored cutoff.

How much caffeine do I get if I have one 240 ml black tea and one 240 ml Americano, and how much will remain after 6 hours?

A 240 ml black tea (47 mg) plus a 240 ml Americano (126 mg) gives a combined dose of 173 mg immediately after consumption: 47 mg + 126 mg = 173 mg (dataset values).

Using this page's decay model (population-average half-life 5.7 hours), after 6 hours about 48% remains, so 173 mg × 0.48 ≈ 83.0 mg would still be present.

"An Americano" is a 240 ml espresso-based drink with 126 mg of caffeine in the dataset used across this site.

For shorter windows, after 3 hours ≈69% remains (173 × 0.69 ≈ 119.4 mg) and after 12 hours ≈23% remains (173 × 0.23 ≈ 39.8 mg); use the caffeine calculator to run different timings or doses automatically.

How do pregnancy, smoking and common health conditions change how long black tea caffeine stays in you?

Pregnancy tends to slow caffeine clearance so the same 47 mg cup will persist longer; health authorities (for example the American College of Obstetricians and Gynecologists and the NHS) recommend keeping daily intake near 200 mg/day during pregnancy to account for slower metabolism (ACOG and NHS guidance reference this recommendation).

Smoking speeds caffeine clearance while certain health conditions that impair liver function slow clearance; the Mayo Clinic notes that pregnancy and smoking are two of the common factors that change caffeine half-life.

"CYP1A2" is a liver enzyme that metabolizes caffeine and is a major reason why genetics, smoking and some drugs change elimination.

Because interactions are individual and some prescription drugs affect CYP1A2 activity, consult a clinician before assuming standard decay applies if you are pregnant, using medications, or have liver disease; for pregnancy-specific dosing see our caffeine and pregnancy guide and the external EFSA guidance on intake limits.

What does EFSA mean by a 200 mg single dose, and how many cups of black tea equal that single dose?

EFSA's 2015 opinion treats 200 mg as a reasonable single dose to avoid acute effects; that single-dose threshold is the one used to assess short-term risks (the European Food Safety Authority sets the 200 mg single-dose recommendation in its 2015 Scientific Opinion).

Because a 240 ml cup of black tea contains 47 mg, four cups (4 × 47 mg = 188 mg) remain under the 200 mg single-dose level while five cups (5 × 47 mg = 235 mg) exceed it, so four cups are just below and five cups go over EFSA's single-dose threshold.

"A single dose" is the total amount consumed within a short window (minutes to an hour) that can produce acute effects such as palpitations or marked sleep disruption.

If you are counting both single doses and total daily intake, combine this calculation with the safe daily limit tool and our comparison page to see how a mix of drinks maps to both limits.

Bottom line

A standard 240 ml cup of brewed black tea contains 47 mg of caffeine and the population-average elimination follows a half-life of 5.7 hours (this page's decay model), so after 6 hours roughly 48% remains—47 mg × 0.48 ≈ 22.6 mg remains from one cup.

The U.S. Food and Drug Administration recommends up to 400 mg/day for healthy adults (the FDA states 400 mg/day), so eight 240 ml cups of black tea (8 × 47 mg = 376 mg) stay below that daily limit while nine cups (9 × 47 mg = 423 mg) exceed it. For pregnancy and single-dose caution the European Food Safety Authority and NHS recommend ~200 mg/day (EFSA and NHS advise ≈200 mg/day), so four cups (4 × 47 mg = 188 mg) are under that threshold and five cups (235 mg) exceed it.

If you drink at 6:00 PM, the page's decay model predicts about 25.6 mg left at 11:00 PM (47 mg × 0.5^(5/5.7) ≈ 25.6 mg), and a large sleep trial showed that higher evening doses can substantially shorten sleep (Drake et al., 2013 documented sleep loss from evening caffeine). Use the site's latest-cup-before-bed tool or the caffeine calculator to plan timing and cumulative mg, or consult our pregnancy guide for pregnancy-specific limits.