This page contains information about the biological half-life of caffeine.

What is the Half-Life of Caffeine?

The half-life of caffeine can be used to calculate how long coffee will affect you after you drink some. Knowing this can help you adjust your coffee intake in order to improve your sleep schedule, or help you determine how often you should drink caffeine in order to maintain a stable level of caffeine through the day.

The biological half-life of caffeine in typical adults is between 5 to 6 hours. This means if you had 100 grams of caffeine, you would have around 50 grams after 5 hours.

Caffeine Calculator

This is a tool to calculate approximately how much caffeine you'll have in your blood based on your intake.

Please note that this is just informative and should not be used for medical or health purposes.

The format of each line is the time you had Caffeine and the amount in milligrams.


Is it bad to drink coffee on an empty stomach?

While coffee is a beloved morning ritual for many, drinking it on an empty stomach may not be the best idea. The high caffeine content can stimulate the production of stomach acid, potentially leading to heartburn or indigestion.

Coffee also contains natural compounds that can stimulate the secretion of gastrin, a hormone that aids in digestion. However, when consumed on an empty stomach, this can cause an overproduction of stomach acid, leading to discomfort.

Moreover, coffee can interfere with our body's ability to absorb certain nutrients, such as iron, due to its high tannin content. This effect is amplified when coffee is consumed without any accompanying food.

Therefore, while a cup of coffee can be a great way to kickstart your day, it's advisable to have it after a meal or alongside some food. This can help mitigate potential adverse effects and ensure you reap the many benefits of coffee without the drawbacks.

Recommended daily caffeine intake for adults

Understanding the amount of caffeine that is safe for daily consumption is crucial for maintaining a healthy lifestyle. While our Caffeine Half-life Calculator provides an excellent tool for tracking the amount of caffeine in your body over time, it's equally important to know the recommended daily intake of caffeine for adults.

The Food and Drug Administration (FDA) suggests a maximum daily caffeine intake of 400 milligrams for most adults. This is roughly the amount of caffeine found in four cups of brewed coffee. However, it's important to note that individual tolerance to caffeine can vary. Some people may experience side effects with lower amounts.

Remember, caffeine is not just in coffee or energy drinks. It's also found in tea, chocolate, some medications, and various foods. Therefore, it's essential to consider all sources of caffeine in your diet when calculating your daily intake.

It's important to note that while caffeine can have positive effects such as increased alertness and improved concentration, excessive consumption can lead to side effects. These can include insomnia, nervousness, restlessness, stomach upset, fast heartbeat, and muscle tremors. Pregnant women, people with certain health conditions, and those who are sensitive to caffeine may need to consume less.