How Much Caffeine is in Tea? Complete Guide

Caffeine content in common tea types

Below are dataset values measured per typical serving. Use the mg/100 ml column to scale for different cup sizes. Values come from standardized beverage analyses used by nutrition databases; for health guidance see FDA and Mayo Clinic.

Why the numbers vary: what affects caffeine in a cup

Tea caffeine isn’t fixed by the leaf type alone. Key factors: leaf grade and age (younger buds concentrate more caffeine), leaf form (broken fannings release more quickly than whole leaves), water temperature, steep time, and tea-to-water ratio. Matcha is powdered whole-leaf, so a teaspoon gives you the whole-leaf caffeine (70 mg in the dataset) rather than an infusion’s fraction.

Measuring loose leaf vs tea bags

Tea bags often contain smaller leaf particles and more mass by volume, producing slightly higher extraction in a short steep than a similar weight of whole-leaf. Commercial bag blends (English Breakfast, Earl Grey) in the dataset are near 47–50 mg per 240 ml. Exact results require weighing the leaf and timing your steep — single gram changes matter.

How tea compares to coffee and energy drinks

Tea is generally lower in caffeine than brewed coffee and energy drinks. For comparison from the dataset: drip coffee (240 ml) ≈ 96 mg, pour-over 240 ml ≈ 145 mg, cold brew 240 ml ≈ 200 mg, and a single 30 ml espresso ≈ 63 mg. Yerba mate (85 mg per 240 ml) can overlap with weaker coffees, while matcha (70 mg) approaches espresso shot levels when consumed as a full cup.

Caffeine decay: how much remains after hours

Population-average caffeine half-life is about 5.7 hours. Approximate retention fractions: after 3 h ≈ 69% remains, 6 h ≈ 48%, 9 h ≈ 33%, 12 h ≈ 23%. Here are concrete mg remaining from typical tea doses in the dataset.

Health, safety, and timing

For healthy adults the FDA cites ~400 mg/day as a safe upper limit; the European Food Safety Authority and Mayo Clinic give similar guidance. Pregnant people are commonly advised to limit to about 200 mg/day. The American Academy of Pediatrics discourages caffeine for adolescents. Individual sensitivity, medications (CYP1A2 inhibitors), liver disease, and smoking (which speeds clearance) change effects substantially.

To protect sleep, avoid caffeine 6–8 hours before bed; because of the 5.7 h half-life some people need to stop earlier. If you track intake and timing, an app like CoffeeLog can calculate cumulative mg and predict residual caffeine at bedtime.

Practical tips to reduce or increase caffeine in tea

• Shorter steep (1–2 minutes) + lower water temperature reduces extraction.
• Use fewer grams of leaf per cup or re-steep leaves (later steeps have much less caffeine).
• Choose white or green teas for lower caffeine; choose yerba mate or matcha for higher caffeine without turning to coffee.
• Herbal tisane if you need zero caffeine.

Sources and next steps

Values above reflect composited beverage analyses used in nutrition databases and are consistent with guidance from USDA FoodData Central, FDA, EFSA, Mayo Clinic, and professional nutrition references. For an exact personal log, weigh servings and steep times and record them — CoffeeLog simplifies this process by converting common servings into mg and tracking timing against sleep.

How do I calculate my cumulative caffeine from several cups of tea during the day?

Calculate cumulative caffeine by summing the remaining milligrams from each serving using first-order elimination with a population-average half-life of 5.7 hours (the decay model used on this site). First-order elimination is a process where the amount of caffeine falls by the same fraction per unit time, so each dose D contributes D × 0.5^(elapsed hours / 5.7) to the current load.

Example: you drink a 240 ml black tea (47 mg) at 09:00, a 240 ml green tea (28 mg) at 13:00, and a 240 ml matcha (70 mg) at 17:00; at 21:00 their remaining amounts are 47 × 0.5^(12/5.7) ≈ 47 × 0.232 ≈ 10.9 mg, 28 × 0.5^(8/5.7) ≈ 28 × 0.376 ≈ 10.5 mg, and 70 × 0.5^(4/5.7) ≈ 70 × 0.615 ≈ 43.1 mg, for a cumulative residual ~64.5 mg. The arithmetic above uses the dataset doses (black tea 47 mg, green tea 28 mg, matcha 70 mg) and the half-life formula; you can reproduce this quickly with our caffeine half-life calculator.

When you plan a long day, compute each cup this way and add them to check against the FDA’s 400 mg/day guideline or any personal limit; the FDA’s guidance is quoted on this site as the safe daily reference for most healthy adults (FDA).

How much caffeine is in matcha per teaspoon and how do I scale it?

The dataset lists matcha (1 tsp, prepared to 240 ml) as 70 mg of caffeine per serving, so one teaspoon is 70 mg according to the per-food compilation used here. Matcha (1 tsp) is 70 mg per 240 ml in the dataset.

Scaling is linear by serving: two teaspoons (same preparation) equal 140 mg (70 mg × 2), and three teaspoons equal 210 mg (70 mg × 3). Using the dataset value and the 5.7-hour half-life, one 70 mg matcha cup leaves about 70 × 0.5^(6/5.7) ≈ 70 × 0.48 ≈ 33.6 mg after 6 hours and about 70 × 0.5^(12/5.7) ≈ 70 × 0.232 ≈ 16.2 mg after 12 hours.

If you want brand-level details or alternative servings with milk, see our matcha caffeine guide and the dataset entries that drive those numbers; if you log teaspoons and timing, a tracker will convert servings into mg automatically.

How long after a cup of tea will caffeine fall below a low-residual benchmark like 10 mg?

Times depend on dose; using a 10 mg residual threshold, a 240 ml black tea (47 mg) drops under 10 mg at about 12.7 hours, a 240 ml green tea (28 mg) at about 8.5 hours, a matcha (70 mg) at about 16.0 hours, and yerba mate (85 mg) at about 17.6 hours. A 10 mg residual threshold is a low-caffeine benchmark used here for practical planning.

Calculations use t = 5.7 × log2(Dose/10). For black tea: t = 5.7 × log2(47/10) ≈ 5.7 × 2.233 ≈ 12.7 h; for green tea: t ≈ 5.7 × 1.485 ≈ 8.5 h; for matcha: t ≈ 5.7 × 2.806 ≈ 16.0 h; for yerba mate: t ≈ 5.7 × 3.087 ≈ 17.6 h. Put another way, if you need very low residual caffeine at bedtime, stop stronger teas (matcha, yerba mate) much earlier than milder green or white teas; the sleep impact of caffeine at higher doses is documented in clinical sleep research (Drake et al., Journal of Clinical Sleep Medicine, 2013).

For a fast personal recommendation based on your bedtime and usual cups, try the latest cup before bed tool which reverses the same math to give the final safe serving time.

How many cups of tea equal a caffeine pill, an energy drink, or the daily safe limit?

An equivalent dose is the number of standard servings that together match the same milligrams of caffeine as another product. For example, using dataset doses, a 200 mg caffeine pill equals about 200 ÷ 47 ≈ 4.3 cups of 240 ml black tea (47 mg each) and about 200 ÷ 85 ≈ 2.35 cups of 240 ml yerba mate (85 mg each), because the dataset lists those exact mg per serving.

Put in context with common products: Bang (300 mg) equals roughly 300 ÷ 47 ≈ 6.4 black-tea cups; Red Bull (250 ml, 80 mg in the dataset) equals 80 ÷ 47 ≈ 1.7 black-tea cups; and a 240 ml cup of drip coffee (96 mg) equals about 2.0 black-tea cups (96 ÷ 47 ≈ 2.04). Use our side-by-side drink comparison to compare these numbers quickly and our safe daily limit tool if you want a weight-adjusted recommendation.

How many cups of tea hit the pregnancy limit set by health authorities?

The pregnancy limit used by EU and U.K. authorities is 200 mg/day; the European Food Safety Authority’s 2015 opinion and NHS guidance both flag 200 mg/day as the working limit for pregnancy. The pregnancy limit is 200 mg/day as set by EFSA (2015) and echoed by NHS guidance (EFSA).

Using the dataset doses, 200 mg/day equals about 200 ÷ 47 ≈ 4.3 cups of 240 ml black tea, about 200 ÷ 70 ≈ 2.9 teaspoons (servings) of matcha, and about 200 ÷ 85 ≈ 2.4 cups of 240 ml yerba mate. If you are pregnant or advising someone who is, combine these arithmetic checks with the full guidance in our pregnancy safety guide (Caffeine During Pregnancy) and, when in doubt, consult the ACOG or your clinician for individualized advice.

Bottom line

A typical 240 ml cup of black tea contains 47 mg of caffeine, green tea 28 mg, matcha (1 tsp prepared to 240 ml) 70 mg, and yerba mate 85 mg (these values come from the per-food dataset used on this site and USDA FoodData Central). The population-average elimination half-life used in our decay model is 5.7 hours, so remaining caffeine after t hours equals Dose × 0.5^(t / 5.7); that formula gives the concrete residuals used above and in our calculators.

For safety benchmarks, the U.S. Food and Drug Administration cites about 400 mg/day as a general safe upper limit for healthy adults (FDA), while the European Food Safety Authority and NHS set about 200 mg/day as the working limit in pregnancy (EFSA). Use the simple arithmetic in this article (Dose ÷ reference mg) and our internal tools—half-life calculator, last cup before bed, and drink comparison—to plan servings that fit those limits and your sleep schedule.