How many cards should a deck have?
October 10, 2026
No study names an ideal number of cards for a deck. There is research on how many cards you study at once, though, and it points somewhere you might not expect.
Bigger stacks space better
In 2009 Nate Kornell had people learn GRE vocabulary with flashcards. Some words were studied as one stack of 20 cards. Others were split into four stacks of 5, each studied on its own. The single big stack did better for 90% of the people in the study.
The reason is spacing. In a stack of 20, each card comes back after 19 others, so you've had time to start forgetting it. In a stack of 5 it comes back almost right away, which feels easy and teaches less. After the first session, 72% of the people said the small stacks had worked better, even though their scores said the opposite.
But a long sitting is tiring
This part isn't from a study. Going through 60 cards front to back is tiring, and stopping halfway feels like failing. The stack in Kornell's study was 20 cards, not 60.
How MindMaxer splits the two
A session here is ten cards, whatever size the deck is. Due cards come from every deck you pick, and you can stop after any round. So you can keep a lot of cards in play, which is what helped in Kornell's study, without having to sit through all of them.
What the research suggests
- Have at least 20 cards in play when you study. That's the stack size that beat smaller stacks in Kornell's study, and it gives each card more time between repeats.
- If a deck is smaller than that, study it together with other decks. Tick a few on the dashboard or use Study all.
- Spread study out over days rather than doing a whole deck in one go. Across hundreds of experiments, spaced study beat the same amount of study done all at once.
The research doesn't say how big a single deck should be, or how many decks a collection should hold. Those are about organizing, so keep each deck to one topic, which keeps its mastery bar meaningful, and use one collection per goal or subject.
Sources
- Kornell, N. (2009). Optimising learning using flashcards. Spacing is more effective than cramming. Applied Cognitive Psychology, 23(9), 1297-1317.
- 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.