How to Study for an Exam in One Day: A 20-Minute Triage and an Hour-by-Hour Plan

It's midterm season, and your exam is tomorrow. If you're figuring out how to study for an exam in one day, here's the honest answer: one focused day can get you through a passing-level review of the material worth the most points, but not mastery of all of it. The day goes to choosing well, answering questions from memory and practicing in the exam's format, and it ends with sleep.

This guide gives you a 20-minute triage, an hour-by-hour plan for a full day, a shorter one for when it's already 8 PM the night before, and the research on all-nighters. If you have three days or more, use the three-day version of our midterm plan instead; for two weeks, the full midterm study plan is the better fit.

Can you study for an exam in one day?

Yes, for a pass on the core material. Two findings set the limits.

Cramming works for tomorrow, then fades. In a classic experiment, students who reread a passage did better on a test five minutes later than students who practiced recalling it. Two days and a week later, the recall group remembered substantially more (Roediger & Karpicke, 2006). John Dunlosky's summary of the study-technique research calls the pattern behind massed practice "quick learning and quick forgetting" (American Educator, 2013). So a one-day push can hold until the exam, but plan on relearning it before a cumulative final.

Cramming feels better than it is. In a flashcard study, spreading study sessions out beat cramming them into the last day before the test, and across three experiments spacing worked better for 90% of participants. Yet after the first session, 72% believed the massed approach had worked better (Kornell, 2009). Use that when you judge your own day: a session that feels smooth is usually one where you're rereading what you already know.

The free forgetting-curve simulator shows the shape of this: what you learn today drops off fast unless you come back to it.

Step 1: a 20-minute triage before you study anything

Set a timer. You're building an exam map, and you're not allowed to start studying until it's done.

1. Format. Multiple choice, problems, short answer, essays, or a mix? Open or closed book? Is it cumulative?
2. Weight and coverage. Which chapters, lectures and problem sets? Use the study guide, the learning objectives, or old exams if your professor posted them.
3. Rank each topic. Give it a points score (how much of the exam it's likely to be, 1 to 3) and a shakiness score (how unsure you are, 1 to 3). Multiply them.

A worked example for an intro biology exam:

Study from the top down. Topics scoring 6 or more get real time; a 2 gets a quick flashcard pass; a 1 gets nothing until the rest is done. A topic you're unsure of but that's worth little isn't worth your morning.

How to study for an exam in one day: the hour-by-hour plan

This plan assumes you start at 9 AM and gives you about 8 hours of actual study with breaks. Shift the clock to fit your day, but keep the order and the stop time.

Then count back seven or more hours from your alarm and be in bed by then.

What a recall round looks like

Close everything. On a blank page, write what you know about the topic: definitions, the steps of a process, how to set up a typical problem. Then open your notes and check it, marking what you left out or got wrong. Turn each mark into a question and answer it from memory again before you move on. The free AP Psychology course's section on retrieving memories covers how retrieval works, which is the skill the exam tests.

The second round, a few hours later, is the closest thing to spacing a single day allows. Don't skip it to cover a new topic.

Keep a misses list

Every question you get wrong goes on one sheet: the question, the right answer, and why you missed it. That list is what you review in the last pass tonight and tomorrow morning.

If it's 8 PM the night before

You have about three hours, so the plan narrows to the top three topics.

That morning session isn't a bonus. With a night's sleep between the two passes, it's your second round.

Should you pull an all-nighter before an exam?

No. If the choice is between three more hours of studying and three more hours of sleep, the research points to sleep.

• In a study of 535 high school students who kept daily diaries for 14 days in 9th, 10th and 12th grades, on days students gave up sleep to study more than usual, they had more trouble understanding material in class the next day and were more likely to struggle on a test or assignment (Gillen-O'Neel, Huynh & Fuligni, 2013). That held no matter how much a student usually studied.
• A meta-analysis of studies that kept people awake for at least one full night found memory suffered when people learned after a sleepless night, with a medium-to-large effect, and also when they were kept awake after learning, with a small-to-medium one (Newbury et al., 2021). The after-learning effect was larger when people were tested right after the lost night instead of after recovery sleep, which is the all-nighter-then-exam pattern. The authors warn that most of the studies had low statistical power and show signs of publication bias, so the exact sizes are uncertain.
• The CDC's guidance is 7 or more hours of sleep a night for adults 18 to 60, and 8 to 10 for teens 13 to 17.

The AP Psychology course's section on sleep covers the stages and what they do. If you can't sleep because of worry, or exam stress keeps coming back, your campus counseling center can help.

How to practice for your exam's format

The triage tells you what to study. The format tells you how.

Multiple choice

Cover the options and answer before you look at them. Then go through the wrong options and say why each one is wrong; they're usually built from common mistakes. AP Statistics has a free walkthrough of a multiple-choice method (read, represent, eliminate, verify) and timed multiple-choice sets if your exam is in stats or you want the method on a real example.

Problem-based exams: calculus, chemistry, physics

Recall here means doing problems with the solution covered. Start with the homework problems you got wrong, then old exam problems. Write a one-page sheet of formulas and when each applies, even for a closed-book exam. Our chemistry guide has a short section on how to take a chemistry exam, and the physics guide has a four-step routine for every problem. When you run out of problems, the free AP Calculus AB and AP Chemistry courses have quizzes throughout.

Memorization-heavy exams: anatomy, vocabulary, a language

The risk is trying to see every term once. Instead, take the ranked topics and drill flashcards in one big shuffled stack rather than small piles, saying each answer before you flip; in the Kornell study, one large stack beat four small ones because each card came back after a longer gap. For anatomy, label diagrams from blank and explain how each structure's shape fits its job. Lykke's free Anatomy and Physiology course groups the body systems into four units, and its sliding filament demo lets you watch the process exam questions ask you to explain. For an intro biology exam, our one-or-two-day biology checklist is a shorter version of this.

Short-answer and essay exams

Guess the prompts from the themes your professor kept returning to. For the top three, outline an answer from memory in 10 minutes (a claim, three pieces of evidence, a counterpoint), then check the outline against your notes and readings.

AP-style exams

The 2027 AP Exams are in May, so a one-day AP exam in October is a unit test in your AP class. Treat it like any other exam with mixed question types: triage by the units it covers, then practice both multiple-choice and free-response questions under time.

Cumulative exams

One day isn't enough to cover a full semester. Weight your triage toward what's new since the last exam plus the topics later units build on, and use your old exams as the question bank.

What to skip when you only have one day

• Rereading the textbook or your notes. It feels productive and it's the slowest way to find out what you don't know.
• Rewriting or color-coding notes. Hours of work, very little recall.
• Topics with a priority of 1 or 2. Come back to them only if the top of the list is solid.
• Watching full lecture videos. If one concept is confusing, find the five minutes that cover it.
• Group study that turns into chatting. Quizzing each other with closed notes counts; comparing how behind you are doesn't.

The morning of the exam

1. Do your 15 to 30 minutes of recall. The misses list and the flashcards you were still missing last night, from memory. No new material.
2. Eat something and get there early.
3. Write down what's worrying you. In a 2011 study in Science, students who did a brief writing exercise about their worries right before an important test scored higher than those who didn't, especially students who usually get anxious about tests (Ramirez & Beilock). If tests make you nervous, try it in your notes app while you wait.
4. Skim the whole exam first and start with what you can answer fastest.

After the exam: don't make the next one a one-day job

Whatever happens, the next exam is probably already on the syllabus. This week, put two or three short review sessions on your calendar for each course and work from questions rather than notes; our guide to what to do when you fall behind on your study schedule shows how to triage a week and make room. If this exam goes badly, what happens if you fail a midterm walks through the grade math and a two-week recovery plan.

For more practice questions on almost any intro course, Explore has free ready-made courses with flashcards and quizzes.