Ace
Short answer: spend the night before an exam on the topics most likely to come up and the ones you're weakest on, and study them by answering questions from memory rather than rereading notes. Stop early enough to get a full night's sleep: sleep helps the brain hold on to what you just studied, and an all-nighter costs more than it gains. In the morning, do a short warm-up from memory, eat, and arrive early.
Is studying the night before an exam worth it?
Yes, within limits. A focused evening can lift your result, especially on topics you half know. What it can't do is replace weeks of spread-out practice: material crammed in one sitting is forgotten faster than material reviewed over several days, a pattern found again and again in research on spacing (Cepeda and colleagues reviewed hundreds of such experiments in 2006). So treat tonight as damage control, and plan to space things out next time.
The biggest mistake isn't starting late. It's spending the evening on activities that feel productive and aren't: rereading the whole textbook, rewriting notes neatly, or making a beautiful summary you'll never get to use.
A plan for the evening
1. Triage: decide what you won't study
You can't cover everything, so choose. Spend ten minutes listing the topics on the exam, then mark each one:
- Likely and weak: study these first. They're where the evening pays off most.
- Likely and solid: a quick check later, nothing more.
- Unlikely: skip them tonight.
To judge what's likely, look at past papers, the learning outcomes in your course handbook, and whatever your lecturer said "will definitely come up". Topics that took several lectures usually carry several marks.
2. Test yourself instead of rereading
Rereading feels comfortable because everything looks familiar, but familiar isn't the same as remembered. Answering questions from memory is harder, and that difficulty is what shows you, and strengthens, what you actually know. In a classic experiment, Roediger and Karpicke (2006) found that students who practised recalling a text remembered far more of it a week later than students who spent the same time rereading it. (Rereading did slightly better on a test five minutes later, which is exactly why it feels like it's working.)
For tonight that means past-paper questions, end-of-chapter questions, or covering your notes and explaining a topic out loud. If you have the lecture slides or PDF, Ace turns them into four-option practice questions checked against your own file, so you can test yourself on exactly what was taught. Our guide to active recall vs rereading explains the method in more detail.
3. Hunt down what you confuse
Wrong answers in exams are rarely random. They come from pairs of ideas students mix up: two similar terms, two drugs with similar names, two formulas that look alike. When you miss a question, ask what you confused it with, and write the two side by side with the difference in one line. Ten such lines are worth more tonight than ten pages of notes. If your exam is multiple choice, read how to study for multiple-choice exams, which covers this in depth.
4. Work in short blocks
Set a timer for 40 to 50 minutes, work on one topic, then take a short break away from your desk. Put your phone in another room for the blocks. A clear block size also makes it obvious when to stop, which matters for the next step.
5. Make one page for the morning
As you go, collect the handful of things you keep getting wrong (a formula, a definition, a list, a confusable pair) on a single page. That page is all you'll look at tomorrow morning.
Should you study or sleep the night before an exam?
Sleep. Sleep isn't time off from learning: while you sleep, the brain stabilises and strengthens memories formed during the day. Diekelmann and Born's 2010 review of the research describes this consolidation in detail. Pulling an all-nighter skips that step and leaves you sitting the exam tired, when attention and recall are at their weakest.
The trade-off has been measured. A study following high-school students (Gillen-O'Neel, Huynh and Fuligni, 2013) found that on days when students gave up sleep to study more than usual, they reported more trouble understanding lessons and were more likely to struggle on a test or quiz the next day, not less. Extra hours of study bought at the expense of sleep didn't pay for themselves.
A practical rule: decide your bedtime before you start, count back from it, and give the last half hour to your one-page summary rather than new material.
What to do the morning of the exam
- Warm up from memory. Go through your one-page summary by covering it and recalling each item, for fifteen to twenty minutes. Don't start anything new.
- Eat something. A normal breakfast beats an empty stomach and a third coffee.
- Pack the night before: ID, pens, calculator, water, so the morning holds no surprises.
- Arrive early, and skip the corridor conversation about topics you haven't covered. It only adds panic.
In the exam itself, read every question carefully, answer the ones you're sure of first, and come back to the hard ones.
Next time: start a week earlier
The same hours spread across a week work far better than one long night. Even three short sessions, spaced a few days apart, beat one cram. Our spaced repetition schedule shows a simple plan, and how to study for exams covers the full approach.
Frequently asked questions
Is it better to sleep or pull an all-nighter before an exam?
Sleep. Sleep helps consolidate what you studied that day, and research on students found that giving up sleep for extra study was followed by more academic problems the next day, not fewer.
How many hours should I study the night before an exam?
As many as fit before a bedtime that still gives you a full night's sleep. Three or four focused hours of self-testing on the right topics are worth more than an unfocused night.
Can you learn a whole subject the night before?
Not properly. You can improve on the topics you half know and fix common mix-ups, but crammed material fades quickly. Prioritise the topics most likely to be examined.
Should I study the morning of the exam?
Briefly. A short warm-up recalling your key facts from memory is useful; learning new material is not.
What's the fastest way to revise the night before?
Answer practice questions from memory on your weakest likely topics, check every answer, and note what you confused. It's more effective than rereading notes for the same time.
Sources
- Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255.
- Diekelmann, S., & Born, J. (2010). The memory function of sleep. Nature Reviews Neuroscience, 11(2), 114–126.
- Gillen-O'Neel, C., Huynh, V. W., & Fuligni, A. J. (2013). To study or to sleep? The academic costs of extra studying at the expense of sleep. Child Development, 84(1), 133–142.
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.
