How much caffeine is in tea? Green, black and herbal compared with coffee

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Tea is often described as gentler than coffee, and a typical cup does usually have less caffeine. But the amount varies far more than most people expect, depending on the leaf, how much you use and how you brew it. This guide explains what changes the caffeine in your cup and what to choose if you want less. It is general information, not medical advice; if you are pregnant, have a health condition or take medication, ask a doctor or pharmacist about caffeine.

Typical amounts

Mayo Clinic's reference chart gives rough figures for an 8-ounce (about 240 ml) cup:

brewed coffee: about 96 mg
brewed black tea: about 48 mg
brewed green tea: about 29 mg
decaffeinated black tea: about 2 mg

Treat these as averages, not facts about your cup. As the chart itself notes, growing conditions and brewing time change the result, and a strong mug of black tea can be well above the average while a light green tea can be well below it.

What changes the caffeine in tea

Steep time. The longer the leaves sit in water, the more caffeine comes out. A quick steep extracts noticeably less than a long one.
Water temperature. Hotter water extracts caffeine faster. That is one reason black tea, brewed near boiling, often ends up stronger than green tea brewed cooler.
Amount of leaf. Twice the leaf means roughly twice the caffeine available.
Leaf grade and part of the plant. Young buds and tips tend to contain more caffeine than older, larger leaves.
The plant and where it grows. Cultivar, climate and shading all play a part. Shade-grown teas tend to be higher.
Broken leaf vs whole leaf. Small broken leaf, as in many tea bags, releases what it contains more quickly, though whether bagged tea ends up with more caffeine than loose leaf depends on the tea and the brewing, and sources disagree.
Matcha. Because you drink the whole powdered leaf rather than an infusion of it, a bowl of matcha can contain more caffeine than a cup of brewed green tea.

Is colour a guide?

Only loosely. It is a common belief that white tea is always lowest and black highest, but caffeine depends more on the leaf and brewing than on the category. A bud-heavy white tea brewed strongly can contain plenty. If you want a reliably low-caffeine cup, choose a decaf or herbal option rather than relying on colour.

Multiple infusions

If you brew the same leaves several times, as many people do with oolong and pu-erh, much of the caffeine comes out in the earlier infusions. Later steeps generally contain less. A quick rinse of the leaves, however, removes only a small share, so it is not a reliable way to decaffeinate tea at home.

Decaf and caffeine-free options

Decaffeinated tea is real tea with most of the caffeine removed, usually using carbon dioxide or a solvent called ethyl acetate. It is low in caffeine rather than free of it, and the process can soften the flavour.
Herbal infusions such as rooibos, chamomile, peppermint, hibiscus and ginger contain no tea leaves and are naturally caffeine-free.
Korean grain teas such as boricha (roasted barley) and oksusu-cha (roasted corn) are caffeine-free and are drunk like water with meals in many Korean homes.
Check blends carefully: a "herbal" mix may include green or black tea leaves, and yerba mate and guayusa, though not tea, do contain caffeine.

How much is too much?

The US Food and Drug Administration has said that 400 mg a day is an amount not generally associated with negative effects for healthy adults. Sensitivity varies widely, however, and lower limits are usually advised during pregnancy. Count all sources together: tea, coffee, soft drinks, energy drinks, chocolate and some medicines.

Tea and sleep

Caffeine stays in the body for several hours, and how long varies from person to person. Sleep specialists commonly advise avoiding caffeine in the six hours or so before bed, and some people need a longer gap. If an afternoon cup of black tea leaves you staring at the ceiling, switch to green tea brewed briefly, a decaf, or an herbal or grain tea after lunch.

Simple ways to cut back

Brew for a shorter time or with cooler water.
Use slightly less leaf.
Make the last cup of the day herbal.
Swap one strong mug of black tea for a lighter green or white tea.

Do you notice a difference between tea and coffee, or between types of tea? Share your experience or ask a question in the comments.