Aurora Flow · Caffeine tools
Caffeine has a half-life of about six hours. The lift fades long before the caffeine clears — which is why an afternoon coffee is still in your bloodstream at 2am. Add what you drank, and see the curve.
Add what you drank
Nothing added yet. Pick a drink above.
The number that matters most is what's left when you lie down.
Median for a healthy adult is around 5.7 hours. Genetics, pregnancy, medication and smoking all move it — some people clear caffeine twice as fast as others.
Total intake today
0mg
Nothing added yet. Pick a drink above.
Largest single dose
0mg
Caffeine is absorbed over roughly 45 minutes and then cleared by first-order elimination. The curve is a one-compartment model with first-order absorption, using the half-life you set.
The two bars measure intake. The curve measures what is still circulating. Those are different quantities, so they get different axes — which is where most caffeine calculators go wrong.
The European Food Safety Authority considers single doses up to 200mg, and habitual intakes up to 400mg per day, unlikely to raise safety concerns for healthy adults. In pregnancy the figure is 200mg per day in total.
This tool reports where your intake sits against those published reference values. It does not calculate a personal safe limit, and it is not medical advice. If you are pregnant, breastfeeding, caffeine-sensitive, or managing a heart condition or anxiety disorder, speak to a doctor about your own ceiling.
Fair question. We sell caffeine, and this tool exists to show you how much of it you are carrying around — including ours.
The reason is that the number is the argument. A brewed coffee is somewhere between 60mg and 180mg and you will never know which one you drank. Our daily dose is 180mg, printed on the bottle, and you can drop it into this curve and watch exactly what it does to your night. One of those is a thing you can plan around. The other is a guess you make twice a day.
So the tool never tells you to buy anything, and it never tells you that you have room for more. It shows you where you are. If the curve makes you drink less coffee and no Aurora Flow at all, it did its job.
Every figure in this tool comes from something we have written up properly. If one of them surprised you, start here.
The half-life
How long caffeine actually lasts
Where the 5.7-hour figure comes from, and why the lift fades hours before the caffeine does.
The night
Caffeine and sleep
What caffeine at bedtime does to deep sleep, even when you fall asleep normally.
The ceiling
How much caffeine is too much?
Where the 400mg and 200mg reference figures come from, and who they do not apply to.
The drop
The caffeine crash, explained
Why the fall feels worse than where you started, and what happens as the curve comes down.
