If you are swapping a daily coffee for black tea, compare what you actually drink: the portion, the brewing method and the refills. Tea is often the lower-caffeine choice at the same volume, but a bigger mug or a longer session can change the comparison. Here is how to make the swap with information you can use.
What the usual tea–coffee comparison actually tells you
For equal-sized servings, brewed black tea usually supplies less caffeine than brewed coffee. In the FDA’s typical-drink table, a 12 US fl oz serving is listed at 71 mg for black tea and 113–247 mg for regular brewed, non-specialty coffee. These are category reference figures, checked on 3 November 2026, not measurements of your tea or café order.
Use that benchmark to frame a question, not to label every tea “low caffeine.” An espresso, a large filter coffee and a bottled coffee drink are different preparations. Likewise, a pot made with a generous dose of loose tea is not interchangeable with a lightly brewed mug. Match the drink type and the volume before comparing the numbers.
Turn a serving figure into the amount you finish
When suitable product information is available, the calculation is: caffeine consumed = caffeine per stated serving × the fraction of that serving you drink. If the label uses mg per 100 mL, multiply that value by your drink volume in mL, then divide by 100. Do not use dry-leaf percentages in this calculation: they do not say how much reached the drink.
Here is a hypothetical example, not a test result. Tea measured at 20 mg per 100 mL would provide 70 mg in a 350 mL mug. Coffee measured at 40 mg per 100 mL would provide 60 mg in a 150 mL serving. The tea is less concentrated, yet the larger portion supplies more caffeine. The point is the arithmetic, not those invented concentrations.
For a takeaway drink, find the actual size and whether the figure is per container or per serving. If you leave half, count half only when the drink is evenly mixed. Adding water or milk changes concentration and flavour; finishing the entire diluted drink still means consuming the caffeine already in it.
Make the tea preparation repeatable
Tea brewing moves caffeine from leaf into water, and steeping time affects the result. Colour and bitterness cannot tell you an exact dose. For a useful home comparison, weigh the leaves, measure the water and time the steep. A scoop is convenient, but it does not give a consistent weight across different leaf shapes.
For flavour, an optional first trial is 2 g of loose black tea with 200 mL of water at about 95°C for 2 minutes, followed by complete straining. This is an editorial starting recipe, not a tested caffeine level or a compulsory standard. If it is too strong, try 90 seconds next time with the other settings unchanged. If it is thin, try 2½ minutes before increasing the leaf.
Those changes help you find a cup you enjoy and can reproduce. They do not establish a fixed caffeine reduction. If you change both the tea and the recipe, keep both in your notes rather than attributing the whole difference to the tea’s name.
Count refills without counting the same pot twice
A second infusion of the same leaves is still a caffeinated drink; it is not a fresh dose of dry tea, either. Record each portion you actually drink, but do not assign the first infusion’s caffeine figure to every later one. Extraction changes across the session, and a single-infusion result does not measure the whole sequence.
If a 400 mL pot is shared evenly between two people, your portion is about 200 mL. Do not count the full pot and then add your cup again. If you refill the teapot with fresh leaves, start a new entry. This simple distinction makes a drink log much easier to interpret.
Try a manageable swap, then review the whole day
Start with the coffee break you most want to change. Record the usual drink and finished volume; on another ordinary day, try one measured serving of tea at that break. Notice whether you add more refills, and keep the other caffeinated drinks visible in the log. A smaller breakfast drink is not automatically a smaller daily intake if the afternoon changes too.
Use five columns: time, drink and preparation, volume finished, caffeine information and refills. Write “unknown” where no suitable figure exists. If reducing caffeine is your aim, a known smaller serving or a suitably labelled decaffeinated option is easier to evaluate than an unlimited pot of tea. Decaffeinated does not necessarily mean caffeine-free.
If caffeine affects your sleep or makes you uncomfortable, adjust the amount and timing rather than relying on a smooth taste. Pregnancy, breastfeeding, medicines and health conditions can change individual advice; discuss these with your health professional instead of treating a general adult figure as a personal allowance.
For cafés: explain the cup and make it repeatable
Explain the serving size, leaf dose, steeping time and refill policy so customers know what their order includes. When caffeine comes up, use this article’s guidance on portions and preparation to explain the comparison, rather than relying on slogans such as “gentle energy” or “no jitters.”
When choosing tea for service, taste it freshly brewed and again after your normal waiting time. Note aroma, strength, astringency and finish. Look for a recipe that staff can repeat easily, fits the pace of service and keeps the flavour within an acceptable range.
Questions you may still have
Is black tea always lower in caffeine than espresso?
No. Espresso is concentrated but is often served in a much smaller volume. Compare milligrams in the portions you finish, using information for those preparations rather than a brewed-coffee average.
Will a quick rinse make black tea decaffeinated?
No reliable caffeine amount follows from a quick rinse. It changes the preparation, but does not verify that the remaining drink is decaffeinated or suitable for someone who needs to avoid caffeine.
What if neither drink has a caffeine label?
Keep the amount and recipe consistent and mark the dose as unknown. A general table can guide a broad comparison, but a personal medical limit needs more reliable product information and appropriate professional advice.