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Spaced Repetition

Spaced Repetition Apps: Let Software Schedule Reviews

Moderate or mixed evidence 5 min read Level: Beginner Reviewed October 30, 2026

Apps like Anki use flashcards and a schedule to bring cards back just before you forget them. See how they work, how to start and their limits.

Evidence rating: Moderate or mixed evidence. The ideas behind these apps, spacing and testing yourself, have strong support (Cepeda et al., 2006; Roediger & Karpicke, 2006). Studies of the scheduling algorithms themselves are fewer. Some work suggests that adaptive schedules can beat fixed ones (Tabibian et al., 2019; Settles & Meeder, 2016), but much of it comes from language learning or lab tasks, and it does not show that any one app is best. How we rate evidence

What it is

A spaced repetition app is a flashcard program with a built-in calendar. You write or download cards. You answer each card and tell the app how hard it was. The app then decides when to show that card again. Easy cards come back after days or weeks. Hard cards come back soon.

Anki is the best-known example, and there are others, such as Quizlet's learn mode, Brainscape and RemNote. They differ in price, design and how much you can change. What they share is the idea that you review a card just before you would forget it.

The app does the bookkeeping, which is why many students like it. You do not have to remember when to review what. But the app only handles scheduling. The quality of the cards, and whether you try to answer before flipping, still depends on you. A student who flips every card without thinking will learn far less than one who stops, tries to answer and rates the result honestly. Before you pick an app, ask three simple questions. Can I edit cards easily? Does it work on my phone and my computer? Can I use it for free, at least for a month? Most students do well with whatever app they will actually open every day. The best app is the one you use, and a plain one you keep up with beats a fancy one you drop after a week.

When to use it

  • You have a large set of facts to learn, such as vocabulary, anatomy terms, dates or formulas.
  • You are studying for a long project, such as a medical or language exam, over months.
  • You have tried paper cards and lost track of which ones to review.
  • You have a phone or laptop and a few spare minutes during the day.

How to apply it

  1. Pick one app and stick with it for a few weeks. Switching apps often wastes the time you spent making cards.
  2. Start small. Make 10 to 20 cards from one lesson, not a whole textbook.
  3. Write each card around one fact or idea. A good card asks a clear question, such as "What does the mitochondria do?", with a short answer.
  4. Look at the front and try to say or write the answer before you flip. Do not just glance at it.
  5. Rate yourself honestly. If you hesitated or guessed, choose the harder rating so the card comes back sooner.
  6. Set a daily limit for new cards, such as 10, and do your due reviews every day. Skipping days builds a pile that is hard to face.
  7. Every week, fix or delete cards that confuse you. Rewrite cards that are too long or too vague.

Step-by-step examples

Example: nursing student learning 200 drug names

  1. She makes cards with the drug name on the front and its class and main use on the back.
  2. She adds 10 new cards each day and reviews what the app shows her, usually 20 to 40 cards.
  3. After three weeks, the cards she knows well show up once every two weeks. The hard ones still show up often.
  4. When she keeps missing two similar drugs, she writes one extra card that compares them directly.
  5. Her daily session takes about 15 minutes on her commute.

Example: high school student learning French verbs

  1. He uses an app with a free deck of common verbs, then edits it to match his class list.
  2. Each card shows an English verb and he types the French form before flipping.
  3. He turns off cards for verbs the class has not covered yet, so he is not learning things out of order.
  4. He keeps a 10-minute session before school and does none on weekends, then catches up on Sunday.
  5. Before a quiz, he also writes full sentences on paper, because the app only tests one word at a time.

Advantages

  • The app tracks timing for you, so you do not need a paper calendar.
  • Cards are available on your phone, which makes use of short breaks.
  • Many apps show your daily counts, which some students find motivating.
  • You can add images, audio or shared decks, which helps with languages and visual subjects.

Limitations

  • Cards work best for facts. They are weaker for deep understanding, essays and multi-step problems.
  • Making good cards takes time, and ready-made decks may not match your course.
  • Phones are full of other distractions. An app session can drift into messages and social media.
  • Research on specific apps is thin. Do not assume a paid app teaches better than a free one or paper cards.

Common mistakes

  • Adding hundreds of cards at once, then facing a huge review pile a week later.
  • Flipping cards without trying to recall first, which turns the app into rereading.
  • Rating every card as easy to clear the queue faster.
  • Making cards with long paragraphs on the back instead of one clear fact.
  • Using the app as your only study method, with no problems, writing or explanation practice.

Recommended next steps

References

  1. 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.
  2. Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255.
  3. Tabibian, B., Upadhyay, U., De, A., Zarezade, A., Scholkopf, B., & Gomez-Rodriguez, M. (2019). Enhancing human learning via spaced repetition optimization. Proceedings of the National Academy of Sciences, 116(10), 3988-3993.
  4. Settles, B., & Meeder, B. (2016). A trainable spaced repetition model for language learning. Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics, 1848-1858.

This guide is general educational information. Study methods work differently for different people, and no method guarantees better grades or results.

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