Tea Caffeine Calculator
Calculate how much caffeine is in your tea based on type, cup size, steeping time, and number of infusions. Compare your daily intake to coffee, energy drinks, and the FDA-recommended 400 mg limit. Everything runs in your browser, completely private.
Your Tea vs Common Drinks
How the Tea Caffeine Calculator Works
This tea caffeine calculator estimates how much caffeine you consume from tea each day based on four key factors: tea type, cup size, steeping time, and number of infusions. Each tea variety has a distinct caffeine range determined by the plant cultivar, leaf maturity, and processing method. Black tea typically contains 40 to 70 mg per 8-ounce cup, while green tea ranges from 25 to 50 mg. The calculator uses a logarithmic steeping curve because caffeine extraction is not linear: most caffeine dissolves within the first 3 minutes, with diminishing returns after that. Longer steeps release more caffeine but at a decreasing rate.
Cup size matters significantly. A small 150 ml gaiwan produces far less caffeine per serving than a large 473 ml mug, even with the same tea. The calculator scales caffeine proportionally based on the standard 237 ml reference size. Multiple infusions are also factored in: each subsequent steep extracts roughly 50 to 70 percent of the previous infusion's caffeine, meaning your third steep has substantially less than the first.
Tea Caffeine Compared to Coffee and Energy Drinks
Tea generally contains less caffeine than coffee, but the gap varies widely depending on the type. A single cup of matcha contains 60 to 70 mg of caffeine, approaching a shot of espresso at 63 mg. Black tea at 40 to 70 mg per cup is moderate, while herbal teas like chamomile and rooibos contain zero caffeine. Yerba mate, while not a true tea, delivers 40 to 60 mg per serving, comparable to black tea.
Compared to energy drinks, tea is considerably lower in caffeine. A 16-ounce Monster has 160 mg and a Bang contains 300 mg, amounts that would require 3 to 6 cups of black tea to match. However, tea drinkers who consume 5 or more cups daily can easily reach 200 to 350 mg, approaching the FDA recommended maximum of 400 mg. This calculator helps you visualize exactly where your daily tea habit falls relative to that limit.
Steeping Time and Caffeine Extraction
The relationship between steeping time and caffeine extraction follows a logarithmic curve. In the first minute, roughly 50 to 60 percent of available caffeine dissolves into the water. By 3 minutes, about 80 percent has been extracted. After 5 minutes, extraction slows dramatically, with only marginal increases beyond that point. This is why a 10-minute steep does not contain twice the caffeine of a 5-minute steep. Water temperature also plays a role: hotter water extracts caffeine faster. Black and pu-erh teas brewed at near-boiling temperatures extract more caffeine per minute than green or white teas steeped at lower temperatures.
Multiple infusions follow a similar decay pattern. The first infusion extracts the most caffeine. The second infusion typically contains 50 to 70 percent of the first, and the third drops to 30 to 50 percent. Gongfu-style brewing with short, repeated steeps distributes caffeine more evenly across infusions compared to Western-style brewing with longer single steeps. This calculator accounts for all infusions when computing your total daily intake.
Tips for Managing Tea Caffeine Intake
If you want to reduce caffeine from tea without switching to herbal, try these strategies. First, shorten your steep time to 1 to 2 minutes, which can cut caffeine by 30 to 40 percent compared to a 5-minute steep. Second, use cooler water, especially for green and white teas, which extracts less caffeine. Third, try white tea, which has the lowest caffeine among true teas at 15 to 30 mg per cup. Fourth, discard the first short steep (a 30-second rinse) which removes a significant portion of surface caffeine. Fifth, limit your daily cups using this calculator to stay well within the 400 mg FDA guideline.
Frequently Asked Questions
How much caffeine is in green tea?
Green tea contains 25 to 50 mg of caffeine per 8-ounce cup, depending on the variety and steeping time. Sencha and dragonwell tend toward the higher end, while bancha and genmaicha are lower. A 3-minute steep at 175 degrees Fahrenheit extracts about 35 mg on average.
Does steeping tea longer increase caffeine?
Yes, but not linearly. Most caffeine extracts within the first 3 minutes of steeping. After that, extraction slows dramatically following a logarithmic curve. A 10-minute steep has only marginally more caffeine than a 5-minute steep. Shorter steeps are an effective way to reduce caffeine intake.
Which tea has the most caffeine?
Among true teas, matcha has the most caffeine at 60 to 70 mg per serving because you consume the entire ground leaf. Black tea is next at 40 to 70 mg per cup, followed by oolong at 30 to 50 mg, pu-erh at 30 to 50 mg, green at 25 to 50 mg, and white at 15 to 30 mg. Herbal teas have zero caffeine.
Is tea caffeine safer than coffee caffeine?
The caffeine molecule is identical in tea and coffee. However, tea also contains L-theanine, an amino acid that promotes calm alertness and may moderate the jittery effects of caffeine. This is why many people experience a smoother energy boost from tea compared to the sharper spike from coffee. The total amount still matters for safety.
How much caffeine is safe per day from tea?
The FDA recommends up to 400 mg of caffeine per day for healthy adults, regardless of the source. This equals roughly 6 to 10 cups of black tea or 8 to 16 cups of green tea, depending on strength. Pregnant women should limit intake to 200 mg per day. Individual tolerance varies based on body weight and sensitivity.
Does the number of infusions affect total caffeine?
Yes. Each subsequent infusion extracts less caffeine than the previous one. The first steep gets about 60 to 70 percent of available caffeine, the second gets 20 to 25 percent, and the third gets 10 to 15 percent. If you drink all infusions, your total caffeine is the sum across all steeps, which this calculator computes automatically.