How Many New Flashcards Should You Add Each Day?

Why one new card turns into several reviews

Practice uses a simple model inspired by the Leitner system, a card-box method for scheduling reviews. A box is just a pile of cards that come back after a set wait. There are five boxes, with waits of 1, 2, 4, 8 and 16 days. A new card answered right goes to box 2, and one answered wrong goes to box 1. A right answer moves a card up one box, and a miss sends it back to box 1.

Follow one card that you answer right every time. It is learned on day 0, then comes back on day 2, day 6, day 14 and day 30. A right answer while already in box 5 counts as mastered, and in Practice the card then stays in box 5 with another 16-day wait, so it keeps returning at a slow rate.

Spacing reviews out is a well-studied idea. One review reported that spacing out repeated encounters with material produces better long-term learning than massed repetition, meaning repeats packed close together (Kang, 2016), and another summarized research showing better final-test performance when sessions are spaced apart (Carpenter et al., 2012). But a meta-analysis of 29 studies, which pools the results of earlier studies, found no significant difference between expanding schedules, where gaps keep growing, and uniform schedules, where gaps stay equal (Latimier et al., 2021). Its authors say the results do not support the belief that gaps should keep growing. So 1, 2, 4, 8 and 16 days is a convenient model, not a demonstrated best.

A worked table: how reviews pile up

Our assumptions: you add the same number of new cards every day starting on day 0, you answer every card right, and you review each card exactly on its due day. Real decks have misses, which send cards back to box 1 and add reviews, so real numbers will usually be higher.

On day 30, reviews reach four times your daily new count, plus the new cards themselves, and they stay there through day 45. After that, the daily reviews grow by one more daily new count every 16 days (day 46, day 62 and so on), because cards in box 5 keep coming back every 16 days. The load keeps growing, but slowly.

Practice does not ask you to set a number of new cards. A session fills with due cards first and uses any leftover room for new ones. When the due pile already fills a session, that session has no new cards.

Turn your time into a number

Pick a daily time budget, time one session to learn your pace, and divide. Because day 30 handles about five times your daily new count in the perfect-recall case, your time budget divided by your seconds per card, then divided by five, gives a rough ceiling for the first month. Later the load keeps growing and misses add reviews, so start well below it.

Clearer cards may also mean fewer misses, and fewer misses mean fewer extra reviews. The guide on how to write flashcards that work covers one idea per card. To see how the boxes move cards in detail, read the Leitner system explained.

Adjust after your first week

Your first number is a guess. After a week, let the due count correct it. The Study tab in Practice shows cards due today, new cards and an estimate of cards due tomorrow. The estimate comes from the box schedule and is not a forecast of what you will remember.

• Add fewer cards if the due count is bigger than one session on most days.
• Add fewer cards if your sessions keep running past the time you set.
• Add fewer cards if many cards keep falling back to box 1.
• Add a few more only if you finish every due card and still have time left.

Your number will also move with your week. See the weekly review plan for placing new-card days and review-only days, the daily review habit guide for keeping the routine small, and the study session length guide for choosing your time budget. When you are ready to try it, open a practice deck and watch the due count for a week.

Common mistakes

• Adding as many cards as you can on a good day. Each new card adds reviews for weeks. Set a daily cap that you could still keep on a tired day.
• Counting only today's session. Look at the cards due tomorrow and at a table like the one above. Today's new cards are next week's reviews.
• Treating the 1, 2, 4, 8 and 16 day schedule as the best possible schedule. It is a simple model. The meta-analysis we cite found no significant difference between expanding and uniform schedules.
• Cramming several facts onto one card to keep the card count low. Split them. One idea per card makes each answer easy to judge as right or wrong. Then adjust the daily number instead.

Frequently asked questions

Is there a recommended number of new flashcards per day?

Not in the sources we checked. The practical answer depends on your time budget, your pace per card and how often you miss. Start small, such as the cautious start in the worked example, and let the due count tell you whether to raise or lower it.

What happens if I add too many new cards?

The due pile grows, sessions run long, and misses add more reviews. In the table, 20 new cards a day means about 100 cards handled on day 30 even with perfect recall. If that happens, pause new cards until the due count falls.

Should I stop adding new cards before an exam?

Our suggestion is to taper new cards in the last days so that your time goes to reviewing and practice questions. The four-week retention plan shows one way to do it. Results vary between people.

Do mastered cards stop coming back?

In Practice, a card marked mastered stays in box 5 and returns after another 16-day wait. That keeps older cards in rotation, and it is also why the review load slowly grows as your deck grows.

Sources

We opened each source below before citing it. See Methodology and Sources for how we check them.

1. Kang, S. H. K. (2016). Spaced Repetition Promotes Efficient and Effective Learning. Policy Insights from the Behavioral and Brain Sciences, 3(1), 12-19. Open the source
2. Carpenter, S. K., Cepeda, N. J., Rohrer, D., Kang, S. H. K., & Pashler, H. (2012). Using Spacing to Enhance Diverse Forms of Learning: Review of Recent Research and Implications for Instruction. Educational Psychology Review, 24(3), 369-378. Open the source
3. Latimier, A., Peyre, H., & Ramus, F. (2021). A Meta-Analytic Review of the Benefit of Spacing out Retrieval Practice Episodes on Retention. Educational Psychology Review, 33(3), 959-987. Open the source