How Much Caffeine Is In A Cup Of Tea | A Clear Guide

Caffeine in tea varies by type, processing, brewing time, and water temperature. On average, a standard 8-oz (240 ml) cup of tea contains 15–70 mg of caffeine, with black tea being the highest and herbal tea the lowest.

Understanding caffeine levels helps tea drinkers choose the right tea for energy, relaxation, or daily consumption.

Tea is one of the world’s most consumed beverages, and one of the most common questions people ask is:
How much caffeine is in a cup of tea?

How Much Caffeine Is In A Cup Of Tea?

Here is a simplified breakdown for an 8-oz cup of brewed tea:

These numbers vary, but they offer a clear baseline for daily tea drinkers.

Full Informative Guide: What Influences Tea Caffeine Levels?

1. The Type of Tea Plant

All true teas (black, green, white, oolong, matcha) come from the Camellia sinensis plant. Caffeine levels differ due to:

• Leaf maturity

• Cultivar

• Processing

• Harvest location

For example, younger tea buds naturally contain more caffeine to protect themselves from insects.

2. Processing & Oxidation

Tea processing changes the chemical composition of leaves:

• Black tea is fully oxidized → releases more caffeine into water.

• Oolong tea is semi-oxidized → moderate caffeine.

• Green/white teas are minimally processed → lower caffeine extraction.

• Matcha is powdered → you consume the entire leaf → highest caffeine for its serving size.

3. Brewing Time

The longer you steep, the more caffeine is extracted:

• 1 minute = mild

• 2–3 minutes = medium

• 4+ minutes = strong, more stimulating

For example, a green tea steeped for 1 minute may contain only 12 mg, but steeped for 3 minutes, it can reach 30+ mg.

4. Water Temperature

Hotter water extracts more caffeine.

• Broken leaf teas (CTC teas, tea bags) release caffeine faster.

• Whole leaf teas release caffeine more slowly.

This is why a typical black tea bag often feels stronger than loose-leaf tea.

6. Matcha vs Regular Tea

Matcha contains more caffeine because:

• You consume whole powdered leaves

• Shaded cultivation increases caffeine

• A typical serving (1g) provides 60–90 mg

Caffeine in Popular Tea Types (Detailed):

1. Black Tea — 40 to 70 mg

Examples: Assam, Darjeeling, Ceylon, Earl Grey
Black tea undergoes full oxidation, resulting in robust flavor and high caffeine.

Best for: Morning energy, focus, replacing coffee.

2. Green Tea — 20 to 45 mg

Examples: Sencha, Longjing, Gyokuro
Green tea is steamed or pan-fired, retaining antioxidants with moderate caffeine.

Best for: Daily sipping, metabolism support, calm alertness.

3. White Tea — 15 to 30 mg

Examples: Silver Needle, White Peony
White tea is the least processed, giving the lowest caffeine—though high-quality buds may contain more.

Best for: Light caffeine intake, hydration, relaxation.

4. Oolong Tea — 30 to 55 mg

Partially oxidized, oolong falls between green and black tea.

Best for: Afternoon energy, digestion.

5. Matcha Tea — 60 to 90 mg

Matcha’s caffeine is comparable to a small cup of coffee because you consume the entire leaf.

Best for: Long-lasting energy, mental clarity.

6. Herbal Tea — 0 mg

Not true tea. Examples:

• Chamomile

• Peppermint

• Rooibos

• Hibiscus

Best for: Nighttime relaxation, caffeine-free hydration.

Tea vs Coffee: Caffeine Comparison:

An 8-oz cup of brewed coffee contains 90–140 mg of caffeine — about 2–3× more than tea.

Matcha is the closest tea alternative to coffee in caffeine strength.

Does Decaf Tea Have Caffeine?

Yes. Decaffeinated tea still contains 2–6 mg of caffeine per cup (not zero).
Herbal teas are the only truly caffeine-free option.

Evidence-Based Insights (Scientific Support)

According to:

1. Tea Association of the USA

Average caffeine in black tea is ~47 mg, while green tea contains ~28 mg per 8 oz.
(Source: Tea Association Caffeine Report)

2. U.S. Department of Agriculture (USDA)

• Brewed black tea: 47 mg

• Brewed green tea: 28 mg

• Brewed coffee: 95 mg
  (Source: USDA FoodData Central)

3. Journal of Analytical Toxicology

Caffeine levels vary significantly with steeping time and water temperature.

4. Harvard T.H. Chan School of Public Health

Tea provides caffeine with L-theanine, promoting calm focus rather than jittery stimulation.

Read Next: 10 Tea Party Food | Classic & Modern Treats to Serve

Take Away:

So, how much caffeine is in a cup of tea?
The answer depends on tea type, leaf grade, and brewing method—but generally ranges from 15 to 70 mg, except for matcha which is higher.

Tea offers a gentler, more balanced energy boost than coffee thanks to L-theanine, making it suitable for both daily drinkers and caffeine-sensitive individuals.

If you’re seeking a strong morning tea or a calming evening cup, understanding caffeine content helps you choose the perfect tea for your lifestyle.