How Many Hours Should I Study For An Exam?

It has been proven repeatedly that cramming course material the night before an exam isn’t the best way to revise and certainly won’t result in you realising your true potential, no matter how much willpower you expend to make it happen.

It might be obvious to state but It is far more sensible to take the approach of investing study time in the days and weeks proceeding your test date. 

How many hours you ultimately need to study for an exam will depend on the complexity and volume of material you are trying to learn, however a study from Colorado State University found that the best performing students (those who achieved an exam score of 90% or more) invested between 1.5hrs – 2.1hrs of study time for every hour of new material presented in class.

As an example of this rule in practice, for a course consisting of 10 x 1hr lectures you should aim to study for no fewer than 15hrs total. 

There are right and wrong ways to accumulate these hours of study of course, and in this article we aim to give you a plan on how to study smarter instead of longer. 

This post explores how many hours you should study for an exam, and how best to approach that study time. If you want to learn how you can best approach the final few hours before entering an exam hall head on over to our guide that weighs the pros and cons of cramming vs chilling

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How long should you study for before taking a break?

Productivity does a nosedive if you never take breaks. 

Our brains are unable to concentrate on the same thing for hours on end, and there’s nothing to be gained by trying to override this neural hardwiring.

You can sit at the desk all day, but after a certain point, your memory simply won’t continue absorbing information, even if you think and feel that it is.

For optimal results, aim to study for no longer than 3 hours at a time to prevent mental fatigue, although there is a growing body of evidence that suggests our brains benefit from a break after 90 minutes of mentally challenging tasks. This is the length of the “basic rest-activity cycle”

It’s natural to worry that by breaking up study sessions with breaks every 1.5hrs that you will lose momentum. 

Counterintuitively it has been proven repeatedly that incorporating regular breaks improves your creativity, your problem-solving ability, and your overall mental capacity. 

Your brain doesn’t actually need all that much time to reset and start absorbing information effectively once again. A micro-break lasting as little as a few minutes can work was an effective study break.

How long before an exam should you start studying?

It’s a good idea to constantly revisit older material throughout a course to refresh your memory however intense and focused studying can begin up to a week before the exam takes place.

You should start studying at least five days before an exam. This gives you enough time to cover the material (in most cases, although somewhat course and subject dependent), but not so much time that it will be pushed out with other pressing matters.

Less than 5 days puts unnecessary pressure on the study time you have remaining, and like watching a ticking clock this time pressure may force you into longer, and ultimately less effective study periods.

The increased stress from starting too late makes it harder to properly absorb information, thus creating a vicious cycle of negative feedback. It is better to begin early and learn a little each day than to cram everything in on the last few days (or forbid the last night – a definite “no”!).

Five days gives you enough time to adjust your schedule too. If you are finding the material straightforward and realize that you know most of it well, you can reduce your study efforts a bit and focus on other subjects. If you are finding it much harder than anticipated, up the ante and pour in more hours.

There’s no harm to starting intense studying earlier than this if you have time, but it may not prove the most effective use of your time if you need to study for multiple subjects at once.

It also has the potential to make you stressed out about the exam by the time it comes around, an unwelcome side effect of having more time to overthink or worry about the outcome.

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What is the total number of hours you should study for an exam?

The number of hours that you need to put into an exam will vary enormously depending on the subject, the length of the exam, and the value of the exam. A three hour exam worth fifty percent of your grade may need significantly more study time than a one hour exam worth only twenty percent.

Your own affinity for the subject will also affect how many hours you need to absorb the material. If you are struggling, allowing yourself more time to memorize and break down difficult concepts and approach them from different angles will help you.

There is no set number of hours that you need to put into an exam, but as relayed above, assigning at least 1.5hrs to each hour of teaching will pay off – more if you are lacking in confidence on the subject.

Don’t compare the amount of time you are dedicating to studying with that to which your fellow students are allowing. This sort of comparison won’t gain you a better mark. You may put a lot more hours into a subject that you find difficult than someone who finds it easy would, and still come out with similar grades.

Similarly, you may need less time to go over the material than someone else who is struggling.

How should you prioritize study subjects?

We all know that the hours in the day are limited. Nowhere more do you feel this squeeze than when preparing for an important exam.

You might want and plan to be studying for fifty hours a week, but life happens. You can become sick, family issues crop up, when your mental health begins to suffer or work calls for you to take on an extra shift.

In such a scenario how should you prioritize to make sure your subjects aren’t suffering?

This depends a bit on what you need to get out of your course, but you could start by identifying areas that are more important than others. If you have any “must pass” modules, they should be at the top of your priority list. Write them down, along with other important modules underneath.

Next, use a highlighter to determine which ones commonly give you issues. If you know you’re having trouble with the mathematics side of your physics course, highlight that. If you’re finding the legal aspect of social studies challenging, color it in.

Now you know what areas are important and what areas you find difficult. If a difficult area is also important, that’s your priority to study, and it should be top of your list.

That isn’t to say you should ignore the “unimportant” areas that you’re also finding difficult, but if your study time is limited by necessity, focus on the important subjects first.

You should worry less about areas that come naturally unless you particularly need to excel in those. While it may be less stressful to study for them, you potentially risk your overall grade if you focus on things you already know!


The number of hours you put into studying a subject should reflect your familiarity with the material, as well as the importance of the exam.

Broadly, studies have shown that the best grades are obtained by students who invest between 1.5hrs – 2.1hrs of study time for every 1hr of teaching time they received. This means that for a modules of 30hrs you should budget between 45hrs – 63hrs for optimal results.

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