How Many Hours Should I Study a Day? What the Data Says

How many hours should I study a day? For a 15-credit semester, US credit rules assume about 5 hours of work outside class on six days a week, and one course needs about an hour. For an exam, divide the hours it takes by the days left. Whatever your number, don't pay for it with nights under 6 hours.

How much college students actually study

Start with what students really do, because it's far below what colleges assume. Laura Crispin and Dimitrios Nikolaou analyzed 7,161 time diaries that US college students kept for the American Time Use Survey during school-year months, from 2003 to 2015. A diary records one day minute by minute, which makes it harder to inflate than a guess at a typical week.

The daily averages include weekends. They also hide a lumpy week: on a given weekday, half of the students without children did no homework at all. Those who did any put in about 3 hours 20 minutes. So the average of about an hour and a half a day is really a few long sessions and several empty days.

Enrollment and family shift the totals. With other factors held constant, full-time students did about 55 more minutes of homework a day than part-time students. Having a child under 18 at home went with about 24 fewer minutes.

How many hours should I study a day for your course load?

US colleges count work in credit hours, and the federal definition says what one stands for. The Federal Student Aid Handbook sets a semester credit hour at no less than an hour of class or direct faculty instruction a week. On top come at least two hours of out-of-class work each week, for about 15 weeks. It's an average over the course, and it's a floor: a school may set a higher standard. Spread over six days a week, by our arithmetic, that comes to:

Fifteen credits make a 45-hour week, class included, which is a full-time job. The diaries fall far short of that. Students without children, about three quarters of them enrolled full time, logged around 11 hours of homework a week, against the 24 to 30 that 12 to 15 credits assume.

In Ireland and the rest of Europe, the unit is the ECTS credit. The European Commission's ECTS Users' Guide sets a full-time year at 60 credits and, in most cases, 1,500 to 1,800 hours of work, classes included. That's 25 to 30 hours per credit, so a 5-credit module stands for 125 to 150 hours from the first lecture to the exam. UK universities count about 10 hours per credit, as our guide to focusing on uni work explains. For an exam, take the total your exam body reports and divide it by the days left.

What counts toward the hours

Out-of-class work means the work itself: reading with notes, problem sets, writing, projects and preparing for exams. Labs, internships, practica and studio work count too. The federal definition gives them credit for an equivalent amount of work, so a lab credit stands for the same three hours a week, however they're split. Time at a desk with your phone in your hand isn't on the list. On StudyDuo, time in the rooms is counted for you: the app totals your minutes, and half an hour keeps a day of your streak.

Do more hours mean better grades?

Hours count, but on their own they predict surprisingly little. Howard Schuman and colleagues ran four major studies and several smaller ones of undergraduates at a large state university. They found "at best only a very small relation between amount of studying and grades", while measures of aptitude tracked grades much more closely.

Surveys like these compare different students, though, and the ones who study longest may be the ones who find a course hardest. Where researchers could isolate the hours themselves, they found a real effect. In one natural experiment, an extra hour a day raised first-semester GPA by about a third of a point; our study hours challenge guide covers it. So plan the hours, and also decide what fills them: practice questions and self-testing, more than rereading.

Is studying 1 hour a day enough?

It depends on what the hour has to cover. So the honest answer to how many hours should I study a day starts with the job the hours are for:

• One course: yes. An hour on six days matches the 6 hours a week the credit rule assumes for a 3-credit course.
• A 15-credit semester: no. It's a fifth of the 5 hours a day those credits assume, and 2 or 3 hours a day still covers only 6 to 9 credits.
• An exam: at an hour every day, 100 hours of preparation take about 14 weeks, and 300 hours about 43. Check your exam's total before settling on an hour.
• Keeping a subject going between terms, or a skill on the side: yes. An hour a day adds up to 365 hours a year, more than the out-of-class work of four 3-credit courses.

An hour every day also builds a different week from the one in the diaries, where half the weekdays had no homework at all. It's easiest to keep when the hour has a fixed start. On StudyDuo, Study Hour gives you one: a single hour of focus without a break, starting at one fixed time that you see in your local time. Afterward, the app checks in on whether you finished what you planned. The study together app page shows how the rooms work.

How many hours of studying is too much?

Too much starts when the hours come out of sleep. J. David Creswell and colleagues tracked first-year students' sleep with Fitbits for a month early in the winter or spring term, at three US universities. Each extra hour of nightly sleep went with a 0.07 higher end-of-term GPA, after accounting for the previous term's GPA. The students averaged 6 hours 37 minutes a night; 21% slept under 6 hours, and only 5% averaged 8 or more. Grouped by sleep, the under-6 group stood out:

Against their own fall GPA, students sleeping under 6 hours fell 0.13 points, while the other two groups held steady. It's a correlation, not an experiment, but it gives a line to plan around: a study schedule that needs nights under 6 hours is too much.

The credit rule gives a second line. Six hours a day outside class on six days is 36 hours a week, more than the rule assumes for 15 credits. With 15 hours of class, it's a 51-hour week. That can work for a few weeks before exams if your sleep holds. As a habit for a whole term, it asks more than the credit system expects of anyone.

The other limit is attention. Real concentration runs out after about 4 hours a day, and nearer 1 for beginners, according to the research on deep work. Longer days only work with lighter tasks past that point, such as flashcards and reviewing mistakes. An 8-hour study day lists the signs that it's time to cut back.

So whatever number you settle on for how many hours should I study a day, test it against two checks each week. Did you sleep 6 hours or more on every night that you studied? And did the hours go into work that produces answers? If both hold, the number is yours to keep or to raise, one block at a time.