What this checker works out
This checker multiplies the number of coffees, teas, energy drinks and colas you have had by typical caffeine figures, and compares the total against the commonly used adult guideline of 400 mg a day.
The typical figures are averages. Real caffeine content varies enormously — a filter coffee can contain three times as much as an instant one, and cup sizes differ by a factor of two before anything else is considered.
Enter your details
Before you total it up
- The figures used are roughly 95 mg per coffee, 45 mg per tea, 80 mg per energy drink and 35 mg per cola.
- A large shop-bought coffee can contain 200 to 350 mg on its own — count it as two or three.
- Include sources that are easy to forget: green tea, chocolate, cold and flu remedies, pre-workout supplements and some painkillers.
- Pregnancy has a lower limit of 200 mg a day, and children and adolescents should have considerably less.
It takes around five to six hours for the body to clear half a dose, and considerably longer for some people. A coffee at 4pm still leaves roughly half its caffeine in your system at bedtime, which is why afternoon coffee affects sleep quality even when it does not stop you falling asleep.
How this calculator works
Four multiplications and a total:
Total = (coffees × 95) + (teas × 45) + (energy drinks × 80) + (colas × 35)
Compared against 400 mg, the commonly used adult guidelineThe 400 mg figure is used by several food safety bodies as an amount not associated with adverse effects in healthy adults. It is not a target, and many people notice effects well below it.
Because the per-drink figures are averages, the total is best read as a rough band rather than a number — someone drinking large filter coffees could easily be at double the figure shown.
Worked example: two coffees and two teas
Using the default figures — two coffees and two teas:
- Coffee: 2 × 95 = 190 mg
- Tea: 2 × 45 = 90 mg
- Total: 280 mg, within the 400 mg guideline
Now swap those two coffees for large takeaway ones at around 300 mg each and the total reaches 690 mg — well past the guideline on four drinks. The number of cups matters far less than what is in them, which is why this checker is most useful as a prompt to look at what you are actually drinking rather than as a measurement.
Common mistakes
- Counting a large shop-bought coffee as one. It frequently contains two or three times the figure used here.
- Assuming decaf is caffeine-free. It typically contains a small amount, enough to matter at high volumes.
- Forgetting non-drink sources. Chocolate, some painkillers and cold remedies all contribute.
- Applying the adult guideline in pregnancy. The recommended limit is half.
- Stopping abruptly after a high intake. Withdrawal headaches are common; reducing gradually avoids them.
Frequently asked questions
How much caffeine is too much?
400 mg a day is the figure most commonly cited as not associated with adverse effects in healthy adults, with a single dose of around 200 mg as a separate reference point. But sensitivity varies considerably — some people experience palpitations, anxiety or disrupted sleep at a fraction of that. The useful test is how you feel and sleep, not whether you are under a threshold.
What is the limit during pregnancy?
NHS guidance is no more than 200 mg a day during pregnancy, roughly two mugs of instant coffee. Higher intakes have been associated with low birth weight and other risks. Caffeine also appears in tea, chocolate, some soft drinks and some remedies, so the total adds up faster than it appears.
How late can I drink coffee?
With a half-life of five to six hours, an afternoon coffee is still substantially present at bedtime. Research has found measurable disruption to sleep quality from caffeine taken six hours before bed even when people did not notice it. If sleep is a concern, a cut-off around early afternoon is a reasonable experiment.
Is caffeine bad for you?
Moderate intake is not associated with harm in healthy adults, and coffee consumption has been linked to some favourable outcomes in observational studies. The concerns are around high intakes, energy drinks in children and adolescents, interaction with anxiety and sleep problems, and use during pregnancy.
Is what I enter stored?
No. Drink counts are processed in your browser and never transmitted or retained.
Related tools
References
- NHS — caffeine guidance, including limits during pregnancy
- Food Standards Agency — advice on caffeine in food and drink and energy drink labelling
Sources are checked at publication and can change — how I choose and check references.