How many mg are in a cup of tea? Your guide to caffeine content

January 6, 2026 •

3 min read

While a standard 8-ounce cup of black tea contains approximately 40–70 mg of caffeine, the reality of how many mg are in a cup of tea is far more complex and depends on several key variables. The exact number can shift based on everything from the type of tea leaf to your brewing technique.

Quick Summary

This guide explores the typical caffeine ranges for various types of tea, from robust black tea to delicate herbal infusions. Learn what factors cause caffeine levels to fluctuate and how to control your intake.

Key Points

Caffeine Varies by Type: Black tea typically has the most caffeine (40–70 mg per 8 oz), while white tea has the least (15–30 mg) among true teas.
Matcha is High in Caffeine: Because the entire powdered leaf is consumed, matcha contains significantly more caffeine than regular green tea (60–80 mg).
Brewing Affects Extraction: Steeping tea for longer or using hotter water will extract more caffeine from the leaves.
Herbal Teas are Caffeine-Free: Most herbal teas, or tisanes, do not contain any caffeine as they are not made from the Camellia sinensis plant.
Decaf Still Has Some Caffeine: Decaffeinated tea is not 100% caffeine-free, retaining a very small amount (typically <4 mg per cup).
Tea Caffeine is Slower-Release: Unlike coffee, the caffeine in tea is absorbed more slowly, which can create a more sustained, jitter-free energy boost.

The Average Caffeine Content by Tea Type

On average, the caffeine in an 8-ounce cup of tea varies widely depending on the type and how it's prepared. Black tea, which is fully oxidized, generally contains the highest levels among the true teas (those from the Camellia sinensis plant), followed by oolong, green, and white tea. Matcha, a powdered green tea where the entire leaf is consumed, delivers a significantly higher concentration of caffeine than a standard green tea infusion. Herbal teas, which are made from herbs, spices, or other plant material, are typically caffeine-free.

Factors Influencing Your Cup's Caffeine

Even within the same type of tea, the milligrams of caffeine can fluctuate considerably due to several factors. These variables give you a surprising amount of control over your final brew.

Tea Variety and Leaf Age: Different cultivars of the Camellia sinensis plant have naturally different caffeine levels. Younger leaves and buds, often used in delicate white teas and high-grade green teas, tend to have higher caffeine content than older, mature leaves.
Processing Method: The way tea is processed impacts how readily caffeine is extracted. While oxidation is a primary differentiator between tea types, processes like roasting can also reduce caffeine content.
Brewing Time: A longer steeping time will draw more caffeine from the leaves into the water. Conversely, a short infusion will result in less caffeine.
Water Temperature: Hotter water extracts caffeine more efficiently. Brewing black tea with boiling water releases more caffeine than brewing green tea with cooler water, as is standard practice.
Leaf Form: Tea bags often contain smaller, broken leaf particles (fannings and dust) with a larger surface area, which means they infuse faster and can sometimes result in more caffeine extraction in a shorter time compared to whole loose leaves.

Tea vs. Coffee: A Caffeine Comparison

It's a common misconception that tea is always low in caffeine compared to coffee. While true on average, specific teas like matcha can rival or even exceed the caffeine of a regular cup of coffee, though the effects are often different due to the presence of L-theanine in tea. A standard 8-ounce cup of brewed coffee contains around 95 mg of caffeine, with a typical 8-ounce black tea cup containing about half that amount. The caffeine in tea is also absorbed more slowly by the body, providing a gentler and longer-lasting lift without the sharp spike and crash often associated with coffee.

Caffeine Content Comparison Table


Tea Type	Caffeine Range (mg per 8 oz cup)	Typical Processing	Notes
Black Tea	40–70 mg	Fully oxidized	Robust flavor, strong energy boost.
Matcha	60–80 mg (per 2 g serving)	Powdered green tea	Consuming the whole leaf results in higher caffeine.
Oolong Tea	30–50 mg	Partially oxidized	Falls between black and green tea in caffeine.
Green Tea	20–45 mg	Unoxidized	L-theanine provides a calm, focused alertness.
White Tea	15–30 mg	Minimally processed	Generally the lowest caffeine of true teas.
Decaffeinated Tea	<4 mg	Processed to remove caffeine	Not entirely caffeine-free, as a small amount remains.
Herbal Tea	0 mg	Caffeine-free naturally	Tisanes from herbs, flowers, or fruits.

Health Effects and Brewing Control

For many, moderate caffeine consumption can offer benefits such as improved mental alertness, but excessive intake may lead to insomnia or jitters. Understanding these variances is essential for managing your personal intake. For example, if you are particularly sensitive to caffeine, you can reduce the steeping time or switch to a variety with naturally lower levels, like white tea. Pregnant women or those with specific medical conditions should pay close attention to their caffeine intake and consult a healthcare provider. For further information on recommended intake levels, you can refer to guidelines from health organizations such as the FDA.

Conclusion

The question of "how many mg are in a cup of tea?" doesn't have a single, universal answer. The caffeine content is a product of several factors, including the tea's origin, processing, and how it is brewed. By becoming familiar with these elements, you can take control of your caffeine intake and select the perfect cup of tea to suit your needs, whether you're seeking a robust pick-me-up or a gentle, calming brew.

Frequently Asked Questions

Among traditional teas, black tea generally contains the highest caffeine level, ranging from 40 to 70 mg per 8-ounce cup. Matcha, a powdered green tea, has an even higher concentration, often between 60 and 80 mg per serving.

Yes, decaffeinated tea still contains a small amount of caffeine. The decaffeination process removes most, but not all, of the caffeine, with most varieties containing less than 4 mg per cup.

The longer you steep your tea, the more caffeine is released from the leaves. For a lower-caffeine brew, use a shorter steeping time. To maximize caffeine extraction, steep for a longer duration, usually 3-5 minutes.

While chemically similar, the effect of caffeine from tea differs from coffee. Tea contains L-theanine, an amino acid that promotes a state of calm alertness, leading to a smoother energy boost without the jittery side effects common with coffee.

Most herbal teas, also known as tisanes, are naturally caffeine-free, as they are not made from the Camellia sinensis plant. However, some exceptions exist, such as yerba mate, which contains significant caffeine.

Higher water temperatures increase the rate of caffeine extraction. Brewing with hotter water will produce a more caffeinated cup than brewing with cooler water, which is why black tea (using boiling water) generally has more caffeine than green tea (using cooler water).

Tea bags typically contain broken leaf particles with a larger surface area. This can cause caffeine to be extracted more quickly and efficiently compared to whole loose leaves, potentially resulting in a higher caffeine content in the same amount of time.