Should you drink coffee before an exam?

cup of coffee

Most of the students (including me) love coffee because it makes us more alert, focused, and overall energized. As a result, many of us have considered taking some coffee before the exam. However, there are some disadvantages related to drinking coffee such as the so-called coffee jitters and increased anxiety. So is it a good idea to drink some coffee before the exam?

Taking an appropriate amount of coffee before the exam is beneficial for most students. Coffee can enhance your mental performance and make you more vigilant. However, this might not apply to every student as each student’s situation is slightly different.

The upcoming sections will cover most of the questions you might have and will help you understand whether a cup of coffee before the exam is something for you.

How coffee can help you with your exam?

Coffee has numerous potential benefits such as better physical performance, lower risk of Parkinson’s, type 2 diabetes, etc (Healthline). But the most important benefit of coffee when taking an exam is that it can improve various aspects of brain function – memory, mood, vigilance, energy levels, reaction times, and general mental function (1, 2, 3).

Here is a full list of benefits that might result from drinking coffee (source Healthline):

  • Increased energy levels and mental performance
  • Could help you reduce body fat
  • Better physical performance
  • Provides you with key nutrients (such as vitamins B2 and B5).
  • Could reduce the risk of type 2 diabetes
  • Could reduce the risk of Alzheimer’s and dementia
  • Could reduce the risk of Parkinson’s
  • Lower risk of several liver diseases
  • Make you less depressed and happier
  • Could protect you against certain types of cancer
  • Lower the risk of cardiovascular disease
  • Make you live longer
  • A source of antioxidants

You can probably see how this could be helpful during an exam when you need your mind to be at its best. What is more, students often take exams in the mornings, which for many students might be a non-optimal time for mental performance. A study has shown that:

“caffeine results in explicit memory enhancement for young adults during their non-optimal time of day – early morning.”

Furthermore, another study showed that workers make fewer errors when they’re caffeinated. While this might be a stretch, based on this study we could conclude that you might make fewer mistakes during the exam as well if you are caffeinated.

So overall, the case for drinking some coffee before an exam is quite strong. But hold your horses, its not all rosy, if you start chugging coffee like crazy it could really seriously harm your health. Therefore, let’s look into some potential disadvantages of drinking coffee.

The potential issues related to drinking coffee

Coffee is a powerful stimulant and can have numerous negative effects on your body. Most importantly it could really disturb your sleep and make you more anxious. This can be detrimental to your performance during an exam.

After all, generally, a lot of students are already nervous before the exam even without drinking coffee. So becoming even more nervous could really negatively affect your performance on the exam. Also, getting a good night’s rest before the big exam day is also crucial – so you don’t want any caffeine disturbing that.

Here is a full list of negative effects of coffee (source Healthline):

  • Increased anxiety and nervousness
  • Disrupted sleep and insomnia
  • Issues with digestion
  • Muscle Breakdown
  • It can make you addicted to caffeine
  • Increased blood pressure and heart rate
  • It could you make fatigued after it leaves your body
  • More frequent urination and urgency

So it appears that there are both advantages and disadvantages to drinking coffee, especially before the exam. So what is the verdict?

The verdict

Overall the benefits of drinking coffee seem to outweigh the negative consequence (Healthline). However, this is the only case when you drink it responsibly. Abusing caffeine could be detrimental to your health. After all, it is a drug. See a table bellow for the relevant advantages and disadvantages of drinking coffee before the exam.

Overall increased mental performanceMight need to got to toilet more often
Less likely to make mistakesMight be more anxious and nervous
Might find it easier to concentrateMight get the coffee jitters

Overall based on my personal experience, I believe that drinking coffee before an exam could be more helpful than harmful – the increased mental performance is really worth a trip to the toilet and most people can easily ignore the coffee jitters or anxiety. However, this only is the case if you can consume coffee properly in a way that does not interfere with your sleep and does not make you overly nervous.

With that being said everyone is different. If you have anxiety issues, high blood pressure, are suffering from insomnia or coffee makes you want to go to the toilet more often – then maybe you should not drink any coffee before the exam (Healthline).

Ultimately, it comes down to how you feel and your personal preferences. So my recommendation is that you should try to experiment and test before the exam whether coffee is something that might be helpful for you. Try to simulate the exam environment (take a test exam at the same time in a day when the normal exam would be held) and try to drink some coffee before and see how it goes.

How much coffee should you drink before the exam?

I have discussed it is important to consume coffee in a responsible manner. Many students abuse caffeine and consume a lot more than they should.

According to Mayo Clinic, for most adults up to 400 mg of caffeine appears to be safe. This is about 2-4 cups of coffee per day. For a better understanding of how much caffeine there is in indifferent kinds of drinks see the table below also you can check this great article by Medical News Today.

Type of drinkCaffeine (mg)
Coffee, Drip115-175
Red Bull (8.2 oz or 242ml)80
Coffee, Espresso (2 ounces or 60 ml)100
Coffee, Instant65-100
Diet Coke45.6
Pepsi One55.5
Tea, iced47
Tea, brewed, imported brands (avg.)60
Tea, instant30
Data taken from University of Utah
How much caffeine is in Starbucks, Red Bull, Coke? - Business Insider
Image taken from Business Insider

After reviewing different websites it is quite clear that the amount of caffeine can really vary from drink to drink. Generally, I just to be on the safe side I would assume that one cup of black coffee can have about 200 mg of caffeine. So you should not drink more than two cups of coffee per day if you are an adult (assuming each cup contains 200 mg).

So should you drink 2 cups of coffee just before the exam? No, of course, not – you should consume coffee in moderation and too much at the same time could be bad for your health. Thus, I would recommend drinking 1 cup of black coffee before the exam.

Differing opinions on optimal coffee intake

Overall my recommendation would be to limit coffee intake to 1 cup per day and to take this cup of coffee in the morning. According to Matthew Walker, the director of UC Berkeley’s Sleep and Neuroimaging Lab, caffeine can be detrimental to your sleep and sleep essential for academic success. It may take up to 12 hours for most effects of caffeine wear off. Thus, you should only take your coffee in the morning if you want to have a good night’s sleep.

With that being said, there are differing opinions on the question of how much coffee should you consume for optimal performance. There are definitely people who will find it impossible to live on just 1 cup of coffee per day. For example, consuming 8 cups of coffee in Finland is quite normal. On the other hand, there are people who say that you should stop drinking coffee immediately.

A more scientific opinion on the question can be found in an article by the Wall Street Journal. That article describes a study by the U.S. Army and the Department of Defense. In that study, researchers tried to determine exactly how much coffee one should drink—and when—to be the most alert and high-functioning.

“The algorithm says a drowsy person should consume 200 mg of caffeine when they wake up, and 200 mg of caffeine four hours later to produce the best possible results. ” Source: Gleim Exam Prep

Also, if you are feeling really nerdy, you can check this website here (2b-Alert). This website is based on real research and can help you to figure out the optimal times for caffeine consumption. With that being said the recommendation is not personalized and the interface is rather complicated – it might take you about 1 hour to really crack it (at least that’s how long it took me).

But why do I still recommend sticking to 1 cup of coffee? While during a difficult exam it might be justifiable to drink 2 cups of coffee, for daily use I would recommend not exceed more than 1 cup of coffee and drink it in the morning.

This is because you do not want coffee to interfere with your sleep which is crucial for academic success (if you don’t believe me – read this article and see for yourself). If you drink coffee in the morning it will last for about 10 hours and then the caffeine crash will kick in, which is great because this will be right around the time you need to go to bed and you will find it easier to fall asleep.

When should you drink coffee for the best effects during the exam?

So you want to drink a cup of coffee as per recommendation, but when should you do it? 1 hour before the exam? 2 hours? 10 minutes?

According to BBC Science Focus:

“Studies have found that the effects of a cup of coffee or a glass of cola are noticeable after just 10 minutes, but the peak caffeine concentration in the blood occurs after 45 minutes.”

So you should drink your cup of coffee about 20 – 30 minutes before the exam. In that way, once you start taking your exam you will be experiencing the peak of the effects of the caffeine.

How long will it last? Well, caffeine will be with you for quite a while, it reaches its halflife (half of it is gone) at around 3 – 5 hours after consumption. And the so-called caffeine crash (i.e. you feel bad) occurs about 8 – 12 hours from when you last consumed caffeine. So generally you do not have to worry about caffeine wearing off because most exams will not last that long.

Of course, if the exam is a long one (like a 5-hour exam), then if the examiners allow you might bring another dose of coffee with you to the exam to keep yourself alert. In fact, that is how I survived a 5-hour examination myself, and believe me, there was no time to spare (there were about 10 questions with the length of answers totaling to 3000 words).

Alternatives to coffee

Although this article is primarily concerned with coffee. You do not have to drink coffee to achieve the same benefits. Many other beverages and snacks contain caffeine. Some of the alternatives include:

  • black tea
  • green tea
  • caffeine pills
  • dark chocolate
  • “mushroom coffee”
  • raw cacao
  • etc.


As you can see when it comes to caffeine, the topic is extremely nuanced. Thus, ultimately it comes down to your own preferences.

Although if consumed correctly coffee could give you a slight edge it will not make you some sort of genius. If you want to get a good score on the exam – you have to study for that. If you have not properly prepared for the exam – it does not matter how much coffee you will drink, most likely you will not get a good score. You should treat coffee as a tool in your student toolkit, but not as some sort of magic cure that will fix all of your problems

Danielius Korsakas

Has a BSc in Economics and currently is pursuing a double master's degree in very fluffy but interesting subjects. Loves learning and building stuff.

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