
Caffeine is traditionally associated with coffee, but you may be surprised how much is also found in tea and soft drinks. Check out the caffeine levels of some common drinks below.
Drink sizes are mostly in 250 milliliters (mL) which is one cup, caffeine is shown in milligrams (mg). Note that an Expresso shot is just a fraction of this size at 30 mL, with energy and soft drinks cans commonly coming in sizes ranging from 250 – 355 mL, so take this into account when calculating how much caffeine you consume each day.
Black tea (250 mL) – 50 mg caffeine
Green tea (250 mL) – 35 mg caffeine
Expresso (30 mL one shot) – 64 mg caffeine
Percolated (250 mL) – 210 mg caffeine
Plunger (250 mL) – 110 mg caffeine
Instant (one teaspoon coffee powder/granules) – 70mg caffeine
Energy drink (250 mL) – 80 mg caffeine
Diet Coke (250 mL) – 32 mg caffeine
Coca-Cola (250 mL) – 24 mg caffeine
Coke Zero (250 mL) – 24 mg caffeine
As a general rule of thumb, tea usually has about half the amount of caffeine compared to coffee, so two cups of tea is equal to one cup of coffee.
However, there are lots of variables that can influence how much caffeine is in your cup of tea or coffee such as:
Caffeine is a simulant, helps combat fatigue and drowsiness and can hang around in your blood system for up to six hours after consuming it. And like many things in life, moderation seems to be the best course. Tea and coffee each have significant health benefits – but too much caffeine is best avoided.
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Written by Paul Taylor
Paul Taylor is a New Zealand–based healthcare content writer with 5+ years’ experience creating patient friendly articles for online pharmacies and health platforms. He specialises in accessible condition guides, prescription FAQs, OTC advice, and health & wellbeing tips, translating complex medicines or health condition information into clear, actionable content. Paul collaborates with the ZOOM Pharmacy clinical team and bases every article on authoritative sources, peer reviewed journals and national clinical guidelines to ensure evidence based, up to date content. His goal is to help readers feel empowered to make informed decisions about their medicines and wellbeing. This content is general information only and does not replace professional medical advice.