The caffeine database and coffee caffeine calculator

Caffeine is a naturally occurring stimulant that mainly works by blocking adenosine receptors in the brain. Adenosine normally helps promote sleepiness, so blocking it can make you feel more alert for a while.

Caffeine does not create energy in the same way food does. Instead, it changes how tiredness signals are perceived. Adenosine builds during the day and binds to receptors that contribute to drowsiness. Caffeine has a similar enough shape to sit on some of those receptors, which can delay the feeling of tiredness.

The effect is not identical for everyone. Genetics, body weight, sleep debt, tolerance, timing, medication and pregnancy can all affect how caffeine feels. CYP1A2 variation is one reason some people clear caffeine faster or slower than others. That is why a late coffee may be fine for one person but disruptive for another.

This page is general information, not medical advice. Individual responses to caffeine vary.

Caffeine can stay in your body for many hours, and a common planning assumption is a half-life of around five hours. That means roughly half the caffeine from a drink may remain five hours later, although this varies widely between people.

Half-life is not the same as how long you feel a coffee. You might stop noticing the lift before all the caffeine has cleared. If you have 100mg of caffeine at midday, a five-hour half-life suggests about 50mg could remain at 17:00 and about 25mg at 22:00. The calculator uses that kind of model to estimate bedtime caffeine.

Clearance varies because genetics affect caffeine metabolism. CYP1A2 variation is one contributor, and pregnancy can slow caffeine metabolism, which is one reason NHS guidance is more cautious during pregnancy and breastfeeding. Sleep disruption also depends on timing and individual sensitivity.

Use these figures as planning estimates rather than a personal medical limit.

FSA guidance commonly references up to 400mg per day for healthy adults, while NHS pregnancy and breastfeeding guidance is more cautious at no more than 200mg per day. Body weight and sensitivity can make a sensible personal target lower than a general adult reference.

The calculator uses body weight because caffeine exposure is often discussed in mg per kg. A smaller person may reach the same mg-per-kg intake with fewer drinks than a heavier person. Sensitivity also matters: someone who feels jittery or sleeps badly after caffeine may choose a lower target even if a general guidance figure is higher.

One-off serving size matters too. A large filter coffee, a double espresso drink or an energy drink can all add up quickly. Other drink values on this page are compiled from reputable public sources including manufacturers, NHS guidance, FSA guidance and nutrition databases. Actual caffeine can vary with preparation and serving size.

This is not medical advice. Follow NHS guidance where relevant and speak to a healthcare professional for personal concerns.

People vary in caffeine sensitivity because metabolism, receptor response, body weight, sleep pattern and tolerance all differ. Genetics, including CYP1A2 variation, can contribute to how quickly caffeine is cleared.

Caffeine blocks adenosine receptors, but the intensity and duration of that effect varies. Some people feel focused after coffee; others feel jittery, anxious or wired for hours. A person who clears caffeine slowly may still have a meaningful amount in their system at bedtime, especially after an afternoon coffee.

Sensitivity can also feel different across life stages. Poor sleep, stress, medication, menopause, illness, changes in routine and pregnancy can all change how caffeine feels. Pregnancy is particularly important because caffeine metabolism changes, which is why NHS guidance recommends a lower daily limit.

Measured caffeine helps remove some guesswork. Counter Coffee publishes lab-tested caffeine information because coffee should be as transparent about caffeine as it is about tasting notes. The right choice may be a stronger morning coffee, a half caf afternoon coffee or decaf later on.

The best stop time depends on the caffeine amount, your sensitivity and your bedtime, but afternoon caffeine is more likely to affect sleep than morning caffeine. This calculator works back from a 22:00 bedtime and estimates a latest third coffee time from the coffees recommended.

Sleep disruption depends on timing and individual sensitivity. Caffeine blocks adenosine, the chemical signal that helps sleepiness build through the day, so caffeine close to bedtime can delay sleep onset or reduce sleep quality. A five-hour half-life means a drink at 15:00 can still leave some caffeine in your system at 22:00.

For cautious goals such as improve sleep, reduce jitters, reduce anxiety or more sensitive users, the calculator aims for a lower bedtime caffeine range. For boost focus, endurance sports or more tolerant users, it allows a higher range. These are planning ranges, not medical thresholds.

If sleep is the priority, consider Easy Afternoon Half Caf earlier in the day and All Day Decaf later.

NHS guidance recommends no more than 200mg of caffeine per day during pregnancy and breastfeeding. Pregnancy can change caffeine metabolism, so caffeine may stay in the body for longer than usual.

Caffeine comes from more than coffee. Tea, cola, energy drinks, chocolate and some medicines can all contribute to daily intake. Because sources add up, it is useful to think in totals rather than single drinks. A mug of filter coffee, a double espresso drink and some energy drinks can each be significant depending on serving size.

Counter Coffee values are based on measured product data, while other drink values on this page are compiled from reputable publicly available sources including manufacturers, NHS guidance, FSA guidance and nutrition databases. Actual caffeine can vary depending on preparation and serving size.

This page cannot give personal pregnancy or breastfeeding advice. If you are pregnant, breastfeeding, trying to conceive or have specific health concerns, follow NHS guidance and speak to a healthcare professional.

Caffeine content varies widely by drink type, serving size and preparation. Coffee, tea, cola and energy drink values on this page are best treated as useful estimates unless they are Counter Coffee products with measured caffeine data.

A mug of instant coffee, filter coffee, tea or an energy drink can all contain meaningfully different caffeine amounts. Espresso is often described as strong, but a small single espresso may contain less total caffeine than a large mug of filter coffee. Double espresso-based drinks can add up quickly because serving size and number of shots matter.

The public drink database combines reputable sources such as manufacturer information, NHS guidance, FSA guidance and nutrition databases. Those figures are helpful for comparison, but real caffeine can vary because of recipe, grind, dose, brew time, cup size and brand.

Counter Coffee products are different because their values are based on measured product data. Most coffee companies publish roast and tasting notes but not measured caffeine levels; Counter Coffee publishes caffeine clarity so people can choose more deliberately.

Wake Up Espresso is the strongest and boldest Counter Coffee for morning routines, while Easy Afternoon Half Caf and All Day Decaf are better fits when you want less caffeine later. First Thing Filter, Uplift Espresso and Refuel Filter sit between those ends of the range.

For mornings, Wake Up suits people who want the highest caffeine option and a bold espresso-style start. First Thing Filter is the second strongest and works especially well for cafetiere or a strong first filter coffee. Uplift Espresso and Refuel Filter are regular-strength choices that fit later morning routines.

For afternoons, Easy Afternoon Half Caf is designed to keep the coffee ritual while reducing caffeine compared with a full-caf option. All Day Decaf is the lowest caffeine choice and works when you want coffee flavour with very little caffeine.

These recommendations are not medical advice. They are practical routine suggestions based on measured caffeine information, because knowing caffeine intake can help people choose coffee that fits their sensitivity, sleep and day.

Counter Coffee product figures come from measured product data, while other drink values are compiled from reputable public sources. The aim is transparency, not false precision.

Counter Coffee lab tests its coffees and publishes caffeine information because coffee should be as transparent about caffeine as it is about tasting notes. Most coffee companies do not publish measured caffeine levels, which leaves customers guessing whether a coffee fits their morning, afternoon or lower-caffeine routine.

For non-Counter Coffee drinks, the database uses reputable publicly available sources including manufacturers, NHS guidance, FSA guidance and nutrition databases. These values are useful for comparison, but they are not guaranteed for every serving. Actual caffeine can vary depending on preparation, serving size, brand recipe, brew method, grind, dose and extraction.

Measured caffeine helps consumers make informed decisions rather than guessing. It is especially useful for people managing sleep, jitters, anxiety, pregnancy guidance, exercise timing or gradual caffeine reduction.

The calculator estimates a daily caffeine limit from body weight and selected sensitivity, then recommends a Counter Coffee routine and a latest third coffee time. It is a planning tool, not medical advice.

Body weight matters because caffeine exposure is often considered in mg per kg. The calculator uses different mg-per-kg assumptions for more sensitive, normal and more tolerant users, then compares the result with common adult reference points such as FSA guidance. It also uses measured Counter Coffee caffeine data where available.

The sleep section calculates the caffeine likely to remain from the first two coffees at bedtime, then uses the third coffee's measured caffeine value to estimate the latest final coffee time that fits the selected bedtime caffeine target. Individual responses vary because caffeine blocks adenosine receptors and metabolism differs between people.

Do not use the calculator instead of NHS guidance or professional advice where that applies.