Caffeine Calculator

Estimate the caffeine content of your cup based on tea type, leaf amount, water temperature, and steep time. Compare caffeine levels across teas and against coffee to make informed choices about your daily intake.

Calculator
Presets:
1 min 10 min
1 10
caffeine per cup
total daily
of 400 mg limit
cups of coffee
Equivalent to

How to Use

  1. 1
    Select your tea type

    Choose from 8 tea types including Black, Green, Matcha, and Yerba Mate. Each has a baseline caffeine value per standard 8 oz cup.

  2. 2
    Adjust steep time and cups

    Set your steep time (1-10 minutes) and number of cups (1-10). Longer steep times extract more caffeine, up to a natural cap.

  3. 3
    Review your results

    See caffeine per cup, total daily intake, percentage of the FDA 400 mg limit, comparison to coffee, and a safety badge.

About

Caffeine is a natural stimulant found in the leaves of Camellia sinensis, the plant behind all true teas. The amount of caffeine in a cup depends on the tea type, processing method, water temperature, steep time, and the ratio of leaf to water. Black and pu-erh teas are fully oxidized and tend to release caffeine quickly, while green and white teas undergo less oxidation and typically yield lower caffeine levels per cup.

Matcha is an exception among green teas because the entire leaf is ground into powder and consumed, so you ingest all of its caffeine rather than just what diffuses into water. Yerba mate, though not from Camellia sinensis, contains caffeine (sometimes called mateine) at levels comparable to or exceeding black tea.

The FDA considers 400 mg of caffeine per day generally safe for most healthy adults, roughly equivalent to 8-9 cups of black tea or about 4 cups of coffee. Individual tolerance varies widely based on genetics, body weight, medication interactions, and habitual consumption. Pregnant individuals are typically advised to limit intake to 200 mg per day. This calculator provides estimates based on published averages and should not replace medical advice.

FAQ

How does tea caffeine compare to coffee?
A typical cup of black tea contains about 47 mg of caffeine, while a cup of brewed coffee has around 95 mg. Green tea averages 28 mg. Matcha is higher at about 70 mg because you consume the whole leaf. Tea delivers caffeine more gradually due to L-theanine, which promotes calm alertness rather than the jittery spike from coffee.
Is there truly caffeine-free tea?
Herbal infusions such as chamomile, rooibos, and peppermint are naturally caffeine-free because they do not come from the Camellia sinensis plant. All true teas (black, green, white, oolong, pu-erh) contain some caffeine. Decaf tea is not completely caffeine-free either, retaining about 2-5 mg per cup after processing.
What is L-theanine and how does it interact with caffeine?
L-theanine is an amino acid found almost exclusively in tea leaves. It promotes alpha brain-wave activity, producing a relaxed but alert mental state. When combined with caffeine, L-theanine smooths out the stimulant effect, reducing jitteriness and improving focus. This synergy is why tea drinkers often report a sustained, calm energy compared to coffee.
Does water temperature affect caffeine extraction?
Yes. Hotter water extracts caffeine faster and more completely. Boiling water (100 C) extracts nearly all available caffeine within 3-5 minutes. Cooler temperatures used for green or white tea (70-80 C) result in lower caffeine extraction, roughly 20-30% less than boiling. Cold-brew tea extracts the least caffeine of all methods.
Does a second steep have less caffeine?
Yes. The first steep extracts roughly 50-70% of the total available caffeine from the leaves. A second steep typically contains about 20-30% of the original amount, and a third steep even less. This is why gongfu-style brewing, which uses short steeps, distributes caffeine more evenly across multiple infusions.
← All tools